Captain Choromatsu invites an interesting detective onto an increasingly dangerous murder case to ease the tension of the crew. / Totoko wants to be a popular idol, but reality is so cruel.

The brothers try their hand as streamers after being chastised by their parents for not having jobs. Later, Iyami uses an experimental detergent to keep his suit clean, but after being confused by the Matsunos as an expensive liquor, is revealed to turn anything invisible (up to a point).

Karamatsu tries to take on various requests from everyone to look like a reliable brother, only to take on more than he can handle, so Choromatsu tries to teach him how to refuse. Totoko begins working at a company, proving to be a handful for her superior Todomatsu. Later, a pair of seiyuu attend a dubbing session of an episode of Mr. Osomatsu, witnessing how the sextuplets do their work.

The Matsunos and Iyami are killed in a freak plane crash, sending them to Hell. In mourning, the others ponder a way to bring the status quo back to its rightful place with the help of someone near and dear to them.