Jake, Nesso, and Emily have been captured by the Mimics. Their friends are determined to rescue them before it's too late, though that's easier said than done. Driven from their home and facing a constant stream of new attacks, Astraea, Zephyr, Pegasus, and Tryn are struggling just to survive another day against Mimics who can kill with a touch and take the shape of any friend or family member.

While Jupiter is focused on returning to Titus, Astraea knows their only hope is to take the fight to the Mimic home world and stop the Mimic queen herself. To do that, they'll need to even the odds of seven friends versus an entire planet. So they come up with a plan to capture the one thing more terrifying than their enemy--the giant snake Lergo.

Seeking out the serpent that almost killed them seems like a terrible idea. But it will take more than one unlikely ally to save their friends--not to mention the universe--and defeat the Mimics for good.