Memempu is a Worker in the underground city of Pinyin, but dreams of becoming a Marker and going off to explore the wild tunnels known as the Labyrinth. On the night of a festival, the Marker duo Walsh and his daugher Lynda return, and Memempu receives a surprising gift. Will she finally be allowed to pursue her dream?

Memempu deciphers the pendant sent by Urorop, revealing it to be a detailed map of the Labyrinth. But before she can head out, a kaiju attacks Pinyin. Her father Gagumber activates a bot he's hidden in the warehouse district, and they face down against the kaiju together.

Memempu finally reaches the Labyrinth and wants to take the shortest route to their goal, but Gagumber continues to shoot down her suggestions. Their bickering only stops when a kaiju attack leaves them separated.

Gagumber and Memempu are arrested in the colony of Jolly-Jolly. They're allowed out for sightseeing while their punishment is determined, but a chance encounter with a woman named Zackletu leads them to bigger trouble!

Meroro takes Memempu and Gagumber to "Windy Hill" Labyrinth, a once-green forest that is beginning to decay. Can Memempu fix the mechanisms causing the Labyrinth's recent climate abnormalities?

Memempu, Gagumber, Zackletu, and Yuri have teamed up for their journey, but one night Memempu gets sick and has a terrifying nightmare. After that, the grown-ups just seem to act more and more strangely...

The team visits the Calacalla Colony to get Yuri treatment. During the downtime, Gagumber runs into an old friend, and Memempu tells Zackletu about her dream...

The jungle heat in the Labyrinth makes things hard going for Team Memempu. But it gets even worse when a sudden downpour leads to flooding that sweeps them away to an isolated island!

After saving the team, Merooro explains further about the natural disasters plaguing the Labyrinth. Gagumber feels threatened by Memempu's growing respect for the bureaucrat.

Merooro brings Team Memempu to Dream Colony to reward them for their aid against Shibito. But a night that should feature a performance from the Colony's foremost diva turns into a farce when the girl escapes her handlers and goes on the run!

Memempu is captured by a Shibito girl who refers to her as a "rainbow child." What do those words mean? And can Gagumber save her before something terrible happens?!