It's great that Mob joined the Body Improvement Club, but he suddenly faints as he's running along the riverside. His wish is to get stronger and to be able to get closer to his beloved Tsubomi-chan. One day, as Mob is feeling troubled, a woman with a strange mask approaches him... Progress toward Mob's explosion: 20%.

The day for the annual marathon and Salt Middle School was drawing nearer. Mob proclaims that if he places in the top 10 he'll tell Tsubomi how he feels about her. Everyone around him cheers Mob on and he starts training hard every day until the day of the event. Meanwhile, Tsubomi and her friend Miki go to Reigen's Spirits and Such Consultation Office with a request. Ritsu happened to be at the office, helping out in Mob's absence, but he hears Tsubomi say something rather surprising.