It's lunch time and I-Pin is invited by Nana Sawada for warning her about the rain shower. As the group eats, Lambo arrives, causing I-Pin to act aggressive since she believes that he is the Broccoli Monster. As I-Pin and Lambo begin to fight, Nana leaves to see a piano recital, leaving Tsuna in charge of the kids. After Nana leaves, Yamamoto arrives for supplementary class homework with Tsuna and brought Gokudera along to help them. However, Gokudera is unhappy when he realizes that he is facing his worst subject: Art.
As the group does their homework, Lambo and I-Pin enter the room and Lambo accidentally destroys Gokudera's work, causing Gokudera to strangle him. However, he stops when Haru arrives to help take care of the kids. When Haru finds out about I-Pin's nearsightedness, she gives her a pair of glasses that belong to her father which initially works but I-Pin removes them since she doesn't have ears.
Lambo starts to tease her again causing I-Pin to attack him with her Gyoza-Kempo. As Lambo is beaten up, he starts to cry and insults I-Pin even more which activates her Pinzu-Timed Super Explosion. Tsuna panics and throws I-Pin out of the window but fails when her hair gets stuck. Lambo tries to use his Ten Year Bazooka on himself, but Reborn uses it to fire at I-Pin instead. As the smoke clears, everyone is surprised to see a young girl in I-Pin's place and realize that I-Pin is actually a girl. I-Pin informs the group that her master sealed the Pinzu-Timed Super Explosion with a password. However, upon seeing Lambo, I-Pin sees him as the Broccoli Monster which happens to unlock the seal and cause a more powerful explosion.
Note: Bold + Italicized = First Appearance