Reigen drags the whole crew to a haunted hot spring and immediately lies his way into disaster while Mob just wants everyone to get along. The show knows exactly what you came for: four characters you already love riffing off each other in absurd situations, with animation that makes even a pointless ghost investigation feel alive. Serizawa finally gets to exist outside his office chair, and the whole thing feels less like filler and more like hanging out with people who've already saved your life too many times to count.

Mob, Reigen, Dimple, and Serizawa, the newest hire at the Spirits and Such Consultation Office, set off for the secluded Ibogami Hot Springs in Zebra Prefecture. The trip costs them nothing: the inn's owner is paying for it after asking Reigen to look into rumors of paranormal activity and help save the business. Ritsu and Teru join the group as well. On the train, a worn-out Reigen and Serizawa doze off and wake to find themselves pulled into an eerie parallel world. Unsure how they got there, the pair must find a way out in time to enjoy their vacation. This one-episode OVA mixes comedy, action, and the supernatural.