After finishing filming a TV mystery mini-drama, Ryugu Komachi and Ritsuko return to 765 Production studios for a break with Mami and the Producer returning as well. Iori decides to treat everyone to some special puddings she bought earlier, but finds out the puddings are gone from the refrigerator. Suspecting the other idols as the culprits, Ami and Mami decide to solve the mystery by playing detectives. As the twins investigate and interrogate the others with their antics, Mami admits to the Producer she feels bored and lonely without her sister but hopes to be famous like Ami and be together again. After clearing almost everyone as suspects, the twins have everyone in the studio pull a scary stunt on Haruka, Chihaya and Miki, which reveals Miki as the real culprit. With the case over, Miki explains she ate the pudding because someone ate her jelly dessert earlier that morning. The twins inadvertently reveal they were the ones who ate it, much to the office's chagrin as the whole thing was their fault in the first place. Makoto also mentions noticing other things going missing from the 'fridge lately, which angers everyone else even further, and everyone begins chasing the twins. In the epilogue, Miki reveals there was only one pudding in the 'fridge when she ate it as, unknown to everyone, it was Azusa who actually ate all of the puddings that morning despite being on a diet.