Whenever there is but a single living soul left on Earth in an After the End scenario, we know that no matter how lonely it seems, there will always be other people left on Earth. Or perhaps zombies. Or a helpful dog. There always are. When it comes to exceptions, there are next to none. And even better: They are somewhere relatively close to him, and will run into him, despite the fact that Earth (or even a major city) is a pretty big place and it should be unbelievably easy to miss each other; generally, however, the second party is making an active effort to find the first, and such handwaves as "I tracked your radio" emerge in short order.
The reason this trope exists, of course, is to take the burden off a single actor. For the most part, stories focused on a single person who never encounters others are boring unless that person is an excellent actor (or the writer is brilliant) - it's interaction that makes for entertainment. Plus, it opens up more potential for conflict, often called the driving force of fiction.
See also There Is Another, Lonely Together. If it really is a chance meeting, it also invokes the trope of It's a Small World After All. If the last man hears a knock and it's a woman, see Exact Words and/or No Man of Woman Born. This is unrelated to Ominous Knocking, but the Trope Namer is an example of both.
- In obscure doujinshi series Mythic Quest this is averted in the Empty Earth arc. Anaya really is the sole human left in the dimension of Earth. There are eventually robots powered back up and A.I., though.
- In the comic Kingdom, it appears all humans have been wiped out, until we discover that there are living populations (albeit frozen ones) in Antarctica and possibly New Zealand.
- Y: The Last Man is both an aversion (Yorrick is the last male mammal besides his monkey, but there's still plenty of women) and a Zig-Zagging Trope. It turns out there are three astronauts aboard the International Space Station, including two men... but an equipment malfunction kills the men on reentry... but the surviving woman is pregnant with a baby boy. Later, Yorrick goes to Japan and stumbles upon another man... but it's actually a fairly lifelike robot. Then he meets Dr. Mann's father, and incorrectly believes it's another robot.
- In the story "The Big Chill" by Alan Moore, the protagonists are the last few living beings left in the universe right before its final heat death. The only additional living thing they encounter is a being who assimilates them and re-creates the universe after it ends.
- The Quiet Earth was advertised as a drama concerning the last man left on Earth, and how he copes with his loneliness. (Not well.) Of course, less than halfway through the film he meets another survivor, and another soon after...
- I Am Legend. In the 2007 film, Will Smith's character is discovered by two survivors, a woman and a young boy. And later, an entire town of survivors pops up.
- A rare example that is far from After the End: In the film Moon, we spend the first half of the film thinking that Sam has gone insane due to loneliness. It later turns out that there are thousands of clones on the moon.
- In Zombieland, we're not really sure if Columbus is the last non-infected human alive. He doesn't seem to be clear on it either. He's not.
- 28 Days Later is another zombie film that starts with one man thinking he's the only one left alive and staggering around a deserted city. It gets worse once the sun goes down, naturally.
- Night of the Comet: Happens multiple times. Just as Regina tells Samantha that they're the only ones left alive, they hear a DJ on the radio. When they get to the radio station, they find the broadcast was automated. Sam starts broadcasting to no-one in particular, just for the hell of it. Suddenly, the "call" light goes off. The caller turns out not to be as friendly as they let on. At the end, Regina admonishes Samantha for crossing the road without looking both ways. Samantha defiantly stomps to the middle of the street, screaming that no-one is left in the city, but is interrupted by a speeding vehicle bearing down on her. The driver, a young male, stops to apologize and warns her to look both ways when she crosses the street.
- Alone on a Ghost Planet with only his Loyal Animal Companion for company, Riddick sees his alien "dog" chewing on something. It's a golf ball.
- While scouting on the barren Death World he and his alien foe-turned-friend have been marooned on, Davidge of Enemy Mine discovers a pile of discarded junk containing a futuristic Pepsi can. His delight at finding proof that humans have been visiting Fyrene IV quickly turns to horror when he discovers a Drac skull among the refuse, evidence that the humans are not friendly, but illegal strip miners and slavers.
- Inverted in Logan's Run; after escaping the city, Logan and Jessica find the Library of Congress, where they meet the Old Man, the last survivor of a post-apocalyptic community in the heavily forested ruins of DC who believed he was the last man alive after burying his parents.
- Fredric Brown's short story "Knock" begins by quoting in full a short story that has become known as the world's shortest horror story: "The last man on Earth sat alone in a room. There was a knock on the door." It's actually a subversion with the last man being in an alien zoo. After the zookeepers leave he propositions for (among other things) the last woman on earth for an Adam and Eve Plot, which she declines. The lock on the man's door is revealed to be a sign of captivity and the knock on the door being a Hope Spot.
- Some time after Brown published "Knock", another author shortened it by one letter to "The last man on Earth sat alone in a room. There was a lock on the door."
- A slight variation of this trope, and possibly an Ur-Example, is in Robinson Crusoe. While he's not the last man on earth, Crusoe has been all alone on a deserted island for some twenty-odd years when he comes across a man's footprint in the sand. He knows it's not his. It's a genuinely creepy moment and loaded with Paranoia Fuel, but ultimately paves the way for the introduction of Friday.
- In "The Silent Towns", one of Ray Bradbury's Martian stories, a man thinks he's the last human on Mars, but discovers - much to his displeasure — that he isn't.
- Averted in Eric. Since the last man on earth is, in fact, Death, he knows full well that no-one's left. However, new matter begins to, very slowly, create itself, and he prepares himself to wait the billions of years necessary until he'll be needed again.
- The science-fiction short story In the Shadow of Bones is eventually shown to be an example. And then the trope is subverted...
- M.P. Shiel's 1901 novel The Purple Cloud has a man believing himself to be the sole survivor after the title phenomenon seemingly kills off all other human and animal life on earth, but he eventually discovers a young woman has also survived the catastrophe. This story was updated and adapted for the 1959 film The World, the Flesh, and the Devil.
- Mau in Nation starts out thinking he's the last man alive, and almost throws himself into the sea until Daphne stops him. As the novel continues more and more people turn up until the eponymous nation is established.
- The Brief History of the Dead is a rare example of a story that averts this, sort of. There is only one person ALIVE in the whole world (a researcher in Antarctica, everyone else having been killed off by an extremely deadly virus), but the story alternates between her and the thousand or so people in the City (the place everyone goes after they die until no one remembers them any more) who are kept there by her memory of them.
- Played With in The Chronicles of Narnia—Jadis really is the last person in her world after using the Deplorable Word to wipe out all other life. However, there are other worlds, so she puts herself into a magical hibernation hoping someone will come across it and trigger her awakening.
- Mentioned in World War Z. While most of the narrators were part of a group during the Zombie Apocalypse, they tell of encountering lone survivors who had been operating as though they were the last human left, and sometimes had been doing so for years before their country's armed forces cleared out all the zombies in the region. With the US Army, those who were decent and reacclimated well to living with other people were dubbed Crusoes. Those who didn't take to it so well are referred to as LaMOE's, (Last Man On Earth) which has the rather unflattering pronunciation of "Lame-o".
- The original novella I Am Legend is somewhat different from the film. Vampires instead of zombies, for one thing. But he's all alone (no dog) until he encounters a woman.
- Doctor Who:
- The show's revival established the Doctor as the Last of His Kind following a Time War that destroyed Gallifrey. Then, three years in, the Master showed up. Opinions vary on whether River Song counts as one of his kind. She's part Time Lord, but didn't come from his planet.
- "The Time of the Doctor" has established that there are other Time Lords, but they're stuck in an alternate dimension
- In "Listen", the Doctor has a theory about the "perfect hiding creature". In the third act, the original Knock story is given a send up when the Doctor finds a time-traveller at the very end of the universe and questions why the traveller's ship is locked, and the time traveller replies that there's something out there that knocks at night. When the Doctor hears it, he gives Clara reassuring explanations about temperature and pressure differentials. It's never revealed which explanation is right.
What's that in the mirror? Or the corner of your eye?What's that footstep following, but never passing by?Perhaps they're all just waiting, perhaps when we're all dead,Out they'll come a-slithering from underneath the bed.
- In "Hell Bent", the Doctor and Clara time-travel to the very last hours of the universe...and hear a knock on the TARDIS door. Four knocks, to be precise. It's the immortal Ashildr / Me.
- Star Trek: Voyager, "Projections." The Emergency Medical Hologram is activated and told by the computer that he's the last person on the ship. As this is still early in the show and he's stuck in Sickbay, he prepares to shut down his program, but suddenly there's a knock at the door.
- Red Dwarf makes this the whole premise of a sitcom. On a mining ship in deep space, a radiation leak kills everyone except one man in a temporal-stasis-field prison cell. He wakes up three million years later, utterly alone. Except for the ship's computer. And a hologram of the one member of the crew he really dislikes. And a humanoid creature that evolved from his cat. And, later, a robot butler. And an alternate-universe version of his ex-girlfriend... And eventually, the entire original crew of the Red Dwarf is reconstructed via nanotechnology.
- Done literally in The Sarah Jane Adventures episode "The Empty Planet"; when Rani wakes up and finds out she's alone, she checks the neighboring houses for other people with no luck. As she's searching for a working TV signal, there's a knock on the front door... which turns out to be her best friend Clyde. Played closer to the spirit of the trope later, when they run across a stranger who was also left behind, then a pair of killer robots... Rani and Clyde are still on the planet because the Judoon grounded them earlier in the series, and said stranger is the reason everyone but him got moved off the planet.
- On The X-Files, Mulder once asked a genie for "peace on Earth", only to find himself the only person left on a vacant planet. Fortunately, while there weren't any other humans, the genie was still around to hear him revoke his wish.
- The Last Man on Earth is about Phil Miller, who believes himself to be the last human left alive. By the end of the first episode he meets Carol, the last woman on Earth. Much like I Am Legend above, this is because Phil left the message "ALIVE IN TUSCON" in a number of locations across North America. He'd given up hope on finding someone before she arrived, but nonetheless, he was trying to be found. And eventually they are joined by Melissa and then Todd, the latter obviously making the show's title something of a lie.
- Fragile Dreams: Farewell Ruins of the Moon starts with Seto burying the only person alive he's ever known, setting off on a epic quest to find any form of life. It ends almost immediately when he finds a girl wandering around.
- In Left 4 Dead 2's aptly named "Last Man On Earth" mode, you are supposedly the last survivor left (even the "normal" infected have somehow disappeared), although each of the rescue vehicle pilots and any other voice-only NPCs who help (or "help") progress, like the gun store owner and the guy in the church, are all still there.
- In the Justice League two-part episode "Hereafter", a supervillain's weapon seemingly vaporizes Superman, but he was actually transported to a strange planet with no intelligent life. Turns out it's a (very distant) Bad Future in which Vandal Savage took advantage of Superman's disappearance to take over the world, inadvertently killing everyone else in the process. Unable to die, Vandal Savage spent the millennia all alone, desperately hoping for some way to atone. Superman's reappearance provided that, and together they were able to Set Right What Once Was Wrong.