The series centers around four fourth graders, Owen Brown, Dana Runson, Jon Doyle and Sydney Lamberti, who are caught up in a war of the gods. The four travel through the Underworlds of different mythologies in an attempt to save their world from ruin.
The books in the series are:
- The Battle Begins
- When Monsters Escape
- Revenge of the Scorpion King
- The Ice Dragon
This series provides examples of:
- All Myths Are True: All the ancient mythologies are real here, though in different realms, with passages allowing access between them.
- Big Bad: Loki is responsible for stirring up chaos in the human and mythological worlds in order to overthrow Odin and rule Asgard.
- Big Red Devil: Hades has this appearance, though he's not evil.
- Bird People: Birdman, from the Babylonian Underworld.
- Bully Bulldog: Mad Dog, from the Babylonian Underworld, who is basically a giant bulldog.
- Cruel Elephant: Mammoth, one of the fire monsters from the Babylonian Underworld, attacks the children and later on aids Loki in destroying Pinewood Bluffs.
- Cyclops: Loki releases a pair into Pinewood Bluffs to build him a suit of armor. Hades tasks the children with capturing them, which they succeed at.
- Damsel in Distress: Dana gets kidnapped and has to rescued by Owen in both The Battle Begins and The Ice Dragon.
- Everybody Hates Hades: Averted. Despite Hades' terrifying appearance and short temper, he proves to be an honorable god who even aids in the battle against Loki.
- Evil Cripple: Loki has a wounded leg and a limp arm due to a prior confrontation with Odin.
- Evil Is Burning Hot: The fire monsters of the Babylonian mythology, which Loki plans on using to burn down the human world.
- Evil Is Deathly Cold: Loki's horns, and his dragon form, are made of ice.
- Gender-Equal Ensemble: The main cast: two boys (Owen and Jon) and two girls (Dana and Sydney).
- Good Scars, Evil Scars: Loki has a large scar across his face, courtesy of Odin.
- Jerkass God: Loki, the Norse trickster god, seeks to burn Midgard (the human world) to ashes in his quest to overthrow Odin.
- Kid Hero: Owen Brown and his friends are fourth graders battling gods and monsters, and doing a surprisingly good job at it.
- One-Winged Angel: In the final book, Loki transforms into an icy dragon to defeat the children and reach Odin's throne. However, Owen returns him to his true form by plunging his sword into his chest.
- Powered Armor: Loki's armor, crafted by the Cyclopes, which heals his weakened body and makes him nearly invincible.
- Right-Hand Attack Dog: Fenrir the wolf serves as this to Loki.
- Savage Wolves: Fenrir, Loki's pet wolf.
- Scaled Up: Loki transforms into the eponymous Ice Dragon to battle the kids in The Ice Dragon.
- Scorpion People: Kingu, the Scorpion King, who was cursed into the form of a scorpion as punishment after his failed war against Marduk.
- Shock and Awe: Dana gains lightning powers after taking Loki's glove.
- Snakes Are Sinister: Fire Serpent and Thornviper from the Babylonian Underworld.
- Sudden Downer Ending: Revenge of the Scorpion King ends this way. The kids help Kingu break his curse and restore him to his true form, and Kingu promptly expels Loki from his underworld and vows to join Asgard to stop him....only for Loki to have his forces destroy the kids' home town, forcing its residents to evacuate, with the kids having to continue their quest, in the process being separated from their families.
