The family goes on a trip, which turns out to be on Rin Rin's submarine! Wataru has a great time with all of them, but then disaster strikes...

Wataru has a strange dream, and wakes up as an invisible ghost! Can the occultist among his sisters, Chikage, return him to his body... or is she the one behind this?

Christmas is coming! Everyone has fun decorating the mansion and choosing presents. Wataru's holy night with his sisters will be truly magical.

All sorts of things are going missing around the mansion! Yotsuba, girl detective, is determined to find the culprit. But what if it's one of them?