A dangerous monster appears in the bathroom at Ernesto and Kevin's apartment, forcing them to use the half-bathroom. Ernesto becomes trapped in the half-bathroom, and enlists Tanya's help to defeat the monster and reclaim the full bathroom.

Kevin is rejected by a butterfly and tries to dig a tunnel to hell, but he unearths a talking skull who wants to hang out. Tanya and Ernesto clash with the butterflies, and Kevin fails to invite his friends to laser tag.

Tanya and Kevin romanticize the ancient world. Ernesto takes them to a museum to show them how terrible old times were, but instead they find an eccentric museum curator and a series of coincidences linking them to the past.