In About Six Hours, I Lose My Virginity to a Fish

Mark caps his graduation by taking down Doc Seismic and rolls straight into a busy summer as Invincible. His mother grows uneasy once she senses he is only staying busy to outrun Nolan's legacy, and she is stunned to find Donald alive when she confronts Cecil. Meanwhile Eve pours her powers into rebuilding parts of Chicago but clashes with her father, who cannot accept her help, and a stowaway Martian joins the Guardians as Shapesmith after being inspired by Martian Man.

After stopping a new Darkwing in Midnight City, Mark is told he must answer to the Atlanteans for Aquarus's death. A trial by combat pits him against a massive kaiju, the Depth Dweller, whose roar wounds him, yet he defies Cecil's orders to save the Atlanteans when the creature turns on them. Back home, Eve is crushed to learn the playground she built has collapsed over unstable ground, and Debbie, worn down by years of feeling like an accessory to Nolan, finally breaks and is comforted by Mark. At the Lizard League's base, King Lizard murders Supreme Lizard and seizes command. In an alternate reality, a mutated and bitter Angstrom interrogates an evil Mark held by that world's GDA, quietly gathering intelligence before slipping away.

A replacement Darkwing debuts and is beaten in Midnight City, and Shapesmith formally joins the Guardians of the Globe. Mark defies Cecil to protect the Atlanteans during his trial, and Debbie's long-buried resentment toward Nolan finally surfaces.

King Lizard assassinates Supreme Lizard and takes over the Lizard League, commanding Salamander, Iguana, Komodo Dragon and an army of mind-controlled humans. Angstrom, now cloaked and cybernetically enhanced, returns and begins scouting alternate versions of Mark to learn how to destroy them.

The title comes from a line Mark speaks in the fifteenth issue of the comic, moments before nearly marrying Queen Aquaria; the show's Atlantis subplot differs sharply from that source. The chapter reveals the middle names of Mark, Amber and William. The dead thugs from the series premiere reappear in Midnight City, confirming no one ever freed them after Darkwing's death.

Two alternate-universe versions of Cecil and Donald, credited as Caitlin and Denise, close out the episode, and a small detail about the Mars file quietly sets up the returning Sequids. J.K. Simmons is credited as Omni-Man despite Nolan never appearing on screen.