Gary is carrying out the final days of his prison sentence aboard the Galaxy One when he meets Mooncake, an alien who is being chased by bounty hunters. Gary swears to keep Mooncake safe, not knowing the alien is a planet-destroying super weapon.

Gary and Avocato must chase down the ruthless bounty hunter Terk, before he can tell the Lord Commander that Mooncake is aboard the Galaxy One.

Quinn realises the only people she can trust are Gary and the crew of the Galaxy One. Meanwhile, as the gravitational disturbance grows, Gary, Quinn, and Avocato's investigation takes them to a bizarre bioluminescent planet.