The protagonist of the novel is a denizen of Moscow named Martin Doogin, a private investigator specializing in cases involving other planets. He has a rare gift to make up interesting and original stories on the spot, which allows him frequent passage through the Gates. Those who know him call him the Walker. One day, a rich client arrives to his office and asks him to find and return his daughter Irina, who has gone off-world. Martin quickly figures she wants to be an Adventurer Archaeologist and finds her on the planet Library, called so because it's covered by mysterious ruins inscribed with symbols no one has been able to decipher. However, just as he finds her, Irina dies in a freak accident (a normally docile alien animal attacks her). Before dying, she gives him the name of another planet. Curious, he goes to that world and discovers another Irina who is alive and well... that is, until she once again dies in a series of unrelated events. He soon finds that there are a number of copies of the girl on different worlds, but each one he finds ends up dying. Later he is told the Gate has split Irina into multiple copies with a Hive Mind of sorts. How? Why, because of Windows, of course. She selected multiple worlds on the screen using the standard Windows Ctrl+click function and hit Enter, expecting the software to randomize her choice. As told by another character, who had something similar happen to him, the Universe does not tolerate doubles and eliminates them through freak events straight out of Final Destination.
Martin is frequently contacted by a Russian FSB officer, who is finally allowed to reveal that Irina's father is their freelance analyst, who recently compiled a classified report with a list of unusual planets that may help reveal Keymaster's past and goal. Of course, Irina uses that list.
With the list he tracks yet another Irina to Bezzar, a planet where people can walk on water due to the extremely-high surface tension (however, spending more than a day on the planet without special equipment is fatal to offworlders). Irina is working with the Bezzarians, a race of man-sized amoebae, on a way to get to the Keymasters' homeworld in order to find out the truth about an ancient cataclysm that destroyed the old galactic community. The Bezzarians build a ship capable of "riding" the wave used by the Gates to link with one another. They jump to what they assume is the Keymasters' home system. When Martin realizes that the Bezzarians intend hostile action, he kills them with his gun (the bullets just pass through, but the heat caused by the friction turns them insane). Just before the Keymasters' black ships arrive to capture the intruders, Irina demands that the pilot kill her to avoid capture, which it does. Martin is captured by returned to Earth. He contacts Irina's father and explains the situation. Not only does the man tell Martin to stop looking, he also pays him the promised amount multiplied by the number of Irinas he found (Martin did put in the effort, after all), before going home to mourn and hope at least one Irina survives.
Still, there's two Irinas left, and Martin continues. In a Breather Episode on Sheali he compares notes with Irina and starts to understand the Keymasters' grand design, but Irina finds yet another way to die. Then he tracks her down to a strange planet called Talisman, covered by a perpetual fog that transforms its star's light into electricity that is absorbed into the ground and powers the constant synthesis and destruction of matter in boxes called "safes". The planet is full of "prospectors" who claim a number of safes and periodically open them to see if anything valuable has been synthesized. Irina is looking for a way to jump-start the next step in human evolution. In the end, it's Martin who figures out how to generate the so-called "detonator", but they are attacked by Aranks who want the secret for themselves. At the moment of choice, Martin chooses to revive Irina (who jumps off a cliff, so that the Aranks can't use her as a hostage) and safely return home. After explaining what he has learned about the planet and the past to a Keymaster (in the form of a story, of course), Martin is told that he no longer needs to tell stories to pass through the Gates. Martin shrugs and tells him that he's used to paying for passage. Martin and Irina return to Earth.
The duology contains examples of the following tropes:
- One-Gender Race: The Dio-Dao are hermaphrodites. When they're 5 months old, a hormonal surge sends them into a mating frenzy, where they seek out the nearest available partner. (This is described as a planet-wide orgy.) Mating nearly always results in a pregnancy (it's not made clear if both partners are impregnated or just one). A month later the pregnant Dio-Dao delivers up to 3 children capable of speech and independent action. With proper medical care the previous generation can live a few weeks after the last birth.
- Absence Makes the Heart Go Yonder: Despite having a boyfriend back on Earth, Irina falls for and sleeps with Martin. The boyfriend is mentioned a total of once time and isn't even given a name.
- Anyone Can Die: Several people risk their lives to help Irina and Martin in their quest. Some don't make it. Irina died 7 times, but the last one didn't count.
- Apes in Space: The Keymasters have an ape-like appearance and are almost entirely covered in fur. Except Martin notes that their hairless hands aren't covered in skin but tiny scales that happen to look like leathery skin from a distance. They also have a short triangular tail that's clearly more reptilian than simian.
- Artistic License: When Ernesto Polushkin lists bizarre fictional names coined by Alexander Grin, he mentions Grey. However, Grey is the character's last name, and his first one is the pretty normal Arthur.
- Ascend to a Higher Plane of Existence: This is implied to be the fate of anyone who attains demigodhood on the planet Talisman after they realize that godlike power and a limited worldview don't mix.
- Beast Man: The Dio-Dao look like small kangaroos with a bit of lizard thrown in.
- Bizarre Sexual Dimorphism: The seal-like sub-sentient creatures travelling with male Geddars are actually their females. Geddars try to hide it — they tell aliens that the law forbids female Geddars and male "lannakhs" to leave their planet. But Dio-Dao already know.
- Bodyguard Crush: Well, though Martin wasn't hired exactly as a bodyguard, he ends up doing nothing but frantically trying to prevent another death of Irina... one of the reasons for being his gradually developing love for her.
- Cataclysm Backstory: It's slowly revealed that an ancient cataclysm struck the previous galactic community that resulted in the Portal Network being shut down and the various cultures being thrown back to the Stone Age, and a number of races even experiencing genetic changes. The cataclysm was actually intentional on the part of the Keymasters who chose to shut down the Gates for reasons of their own. Millennia later, they have decided to try again.
- City Planet: Arank is entirely covered by a single city.
- Common Tongue: One intentional side effect of using the Gates is that all travelers automatically learn the tourist language. It's a fairly simple language developed by the Keymasters to suit most races capable of speech. Those races who aren't instead learn the equivalent sign language.
- Crystal Spires and Togas: The Aranks are a Higher-Tech Species who might look this way to humans.
- Dying Clue: When an Irina dies, she manages to tell Martin something about a "Marge". Martin assumes she has a pet named after a character from The Simpsons. Later, though, he figures out that "Mardj" is the politically-correct American name for the planet Fakyu (from the native word for "planet").
- Energy Weapon: The Aranks have both regular guns and "heat rifles" that act like typical laser guns.
- Everything Trying to Kill You: It seems Creation itself rebels whenever the Gates malfunction and create copies of people. The duplicates either die through a series of unrelated events or simply vanish if they try to use the Gates again.
- Failed Future Forecast: When a Canadian tourist asks Martin about hotels in Moscow, Martin recommends the Rossiya as something less comfortable but cheap and in a good location. The Rossiya Hotel was closed down and the building demolished in 2006.
- Flying Saucer: Keymaster ships are of this type.
- Genetic Memory: The Dio-Dao transfer half of their memories to their offspring (they can pick which memories). It's possible to copy everything, but it's considered immoral and can't be done deliberately.
- Human Aliens: Two humanoid races are described. Neither can cross-breed with humans, but otherwise there's no differences to speak of.
- The planet Prairie 2 is colonized by American settlers but has a primitive native population (called Indians by the colonists).
- The Aranks are a highly-advanced race visually indistinguishable from humans. However, the concept of the "meaning of life" is foreign to them, and every other race's obsession with it seems ridiculous to them.
- Idiosyncratic Episode Naming: The 7 chapters are named after the 7 colours of rainbow. Each chapter is dominated by that colour.
- Imported Alien Phlebotinum: While it's implied that the various intelligence agencies have managed to get their hands on some advanced alien tech (including Arank "heat rifles"), the technology is too advanced for human science to comprehend, meaning no reverse-engineering is possible. Hell, they can't even recharge the rifles once the batteries run out.
- Arank law forbids them from giving technology to less advanced races. There are laws that supersede this, but they're invoked on a case-by-case basis. Martin ends up getting his hands on an Arank "heat rifle" after killing an Arank assassin sent after him. By Arank law, Martin can lay claim on the attempted killer's property and spouse (he refuses the latter, which the local police admits is the smart choice, as the wife would then divorce him, and he'd have to pay alimony). While the Aranks are initially reluctant to give Martin the weapon, they know that it's too advanced for human science and is only good for a few shots anyway.
- The "circuit boards" and rosy powder from Talisman fetch good price on Earth, despite nobody knowing what they were meant for.
- Interspecies Adoption: On Sheali Martin ends up saving the life of a local girl and being forced to adopt her. Irina cracks jokes about an "interplanetary paedophile", but demonstrates that she can be a capable mother, despite being in her late teens herself. The adopted girl ends up becoming the Chosen One prophecised to wake her planet from its millennia-long stasis where rigid laws allow the population not to think. She ends up becoming the queen equivalent and legally adult and staying home.
- Jealous Romantic Witness: Irina is split into seven copies of herself which are located on different planets and can sense each other's feelings (and get killed off one by one as nature struggles to bring order back). When Martin starts a romance with the fifth Irina, the two other remaining ones can't help but sense her feelings all the time, including when Martin sleeps with her, and go crazy with jealousy.
- Lizard Folk: The Geddar. They are frequently seen with lizard-like pets (who turn out to be their females who are non-sentient). Martin believes that the Keymasters are reptilian as well, despite their ape-like appearance and fur.
- Mind Meld / Hive Mind: Keymasters and Irina.
- Each Keymaster is a distinct personality, but what one of them knows, all know.
- The various copies of Irina receive the memories of the dead duplicates. They mistakenly begin to suspect Martin of murdering their copies, as he always seems to show up just before they die.
- Most Writers Are Writers: While Martin isn't a writer, he does have the ability to make up interesting and original stories on the spot, which is what makes him such an effective offworld detective. He also states in the first part that he has a degree in literature.
- Named After Their Planet: Played straight for the Aranks (from Arank), the Bezzarians (from Bezzar), and the Sheali (from Sheali). Averted with the Dio-Dao whose homeworld is called Fakyu (for obvious reasons, Americans prefer to call it "Mardj", meaning "planet" in Dio-Dao).
- New Old West: The planet Prairie 2 is, basically, the Old West IN SPACE!. Settled by American colonists, it has a race of primitive Human Aliens who are derogatorily called Indians. The way of the gun is followed by many. Martin witnesses a shootout and notes that it looks very much like a Western.
- Nuke 'em: Apparently, the first thing the US did when the Keymasters' flying saucers descended all over the world was to try to nuke their mothership. The result? Not even a scratch on the ship. The Keymasters said nothing regarding the "unfortunate incident", and even helped the humans clean up the contaminated territory and presented anti-radiation medicine to those affected. The President ended up hurriedly apologizing and punishing the designated patsies.
- Obstructive Bureaucrat: Dio-Dao and Sheali, for different reasons and with different results.
- The Dio-Dao are obsessed with bureaucracy, which is strange for a species whose lifespan is 6 months. As one Dio-Dao and Martin explain, the comprehensive system of rules and laws does save time for the natives, and is only obstructive to aliens, who may create problems and waste locals' precious time.
- As for Sheali, their laws and traditions act as a brain substitute, allowing them to spend their adult life without thinking. This prevents them from becoming Transhuman and causing another catastrophe.
- Omniglot: Irina speaks Russian, English, French, Latin, Greek, German, and Spanish, not to mention the tourist language automatically learned by anyone traveling through the Gate.
- The Omnipotent: Anyone who travels to Talisman and gets "detonator" becomes this. The Keymasters as a race did it, as well at least two unknown races. Martin also becomes this, but then rejects it.
- The Paralyzer: Aranks have beams that paralyze muscles. Apparently, they work on most races with muscles.
- Planet of Hats: Most visited planets are. Most of this is hypothesised to be either results of the catastrophe caused by newly-formed "gods" or the measures taken to prevent becoming Transhuman.
- Prairie-2 is Wild West, where the Indians equivalent hate Keymasters like a toothache.
- Arank is Crystal Spires and Togas, where natives aren't afraid to die.
- Fakyu is Obstructive Bureaucracy populated by short-lived One-Gender Race obsessed with alien religions.
- Bezzar is a planet of Starfish Aliens with Organic Technology, but surprisingly human-like psychology and desire to revenge. They turn out to descend from Humanoid Aliens, possibly Keymasters.
- Sheali is Diesel Punk Obstructive Bureaucracy where population doesn't think.
- Library and Talisman are Single Biome Planets After the End: no native population, little to no wildlife, artefacts with unknown purpose all over the planet. Each is populated by a few thousand people trying to discover their secrets or at least get some quick money.
- Library is a tropical beach without trees and just narrow channels for seas.
- Talisman is more like warm foggy Klondike.
- Geddar (never visited) has Proud Warrior Race of Scary Dogmatic Aliens, but surprisingly level-headed and friendly. Also with Bizarre Sexual Dimorphism and probably a Physical God.
- Political Overcorrectness: Due to the unfortunate similarity of the Dio-Dao's homeworld's name (Fakyu) to a well-known English curse, the US government has decided to call the planet Mardj after the Dio-Dao word for "planet". Since the human-oriented Gates use a catalog designed by Microsoft, the name Mardj is used by any human traveler to that world.
- Portal Network: The Gates set up by the Keymasters that join all known worlds together. Earth is added to the network several years before the events of the novel.
- Proud Warrior Race Guy: The Geddar are a race of Lizard Folk who always walk around with swords. Even their deity is a warrior.
- Secret Test of Character: It's implied that the stories that the Keymasters require for passage through the Gates are this. Or, they're just bored.
- Serial Homewrecker: Martin prefers to date married women who are fine with their own husbands and are only looking for a casual affair. That's because he doesn't feel ready for a committed relationship and wants to make it as clear as possible he isn't planning marriage. Also, he likes a mature and experienced woman, because Age-Gap Romance is gross. In the end, he is in love with and engaged to Irina, unmarried, eighteen years his junior.
- Shout-Out: On Prairie 2, a bartender lists off a number of alcoholic beverages and cocktails, all of which are actually named after Russian science fiction novels: Escape Attempt by the Strugatsky Brothers, The Culling by Oleg Divov, Ring of Darkness by Nick Perumov, Wolfish Nature by Vladimir Vasilyev, and Lukyanenko's own Sea of Glass and Line of Delirium.
- Starfish Aliens: The Bezzarians are man-sized amoebae. They utilize Organic Technology.
- Sufficiently Advanced Alien / Physical God: Keymasters, because they got omnipotence, but refused to Ascend To A Higher Plan Of Existence.
- Unfortunate Name: Martin I. Doogin, named after Jack London's Martin Iden. Has to suffer never-ending Martini jokes (offscreen, fortunately). Then he meets Ernesto Polushkin, named after Ernesto Che Guevara. Both agree Ernesto has it worse.
- We Are as Mayflies: Everyone compared to the Keymasters. Inverted with the Dio-Dao, whose lifespan is only about 6 months.
- Hidden Text: Each of the 7 chapters starts with a word from the Russian mnemonic for colors of the rainbow (equivalent to English "Roy G. Biv"). In the Orange chapter, a cowboy appears whose name is not revealed unless you read only the capital letters (in the Russian version) of the paragraph describing him. The name turns out to be "Semetskiy", which is a well-known gag by Russian sci-fi authors to always include a bit character with that name, as a joke on a real-life sci-fi fan by that name (the character usually dies).
- Weird Currency: The Keymasters only accept interesting and original stories as payment for passage through the Gates. Since the first time a person goes through they usually tell their life's story, it usually works, as each person's life is unique. However, many people end up getting stuck on other planets, as they can't think of a good story.
