Hide and Seek on a Cruise Ship is the 30th episode of the Katekyo Hitman Reborn! anime.
Nana Swada had just won a ticket to Paradise Island and showed them to Tsuna. Tsuna approves, thinking that he and Kyoko will be the one to go, but Nana shows that there are only 2 tickets and asked Tsuna to go with her. Reborn agreed that it will be a vacation for just the two of them. Once on the cruise ship, Tsuna marveled at it, saying that it's his first time to be on board on a luxurious ship. He and Nana went to the Dining Area. They asked for their table but finds out that their food has been finished. Tsuna went near the table only to trip on Lambo and falls.
Soon, Yamamoto, I-Pin, Haru, Futa, and Bianchi appears. Yamamoto said that they were invited by Reborn. Tsuna panics when he finds out that Reborn is on board and that Reborn and Bianchi knock the guards to sneak in. Reborn appeared in a Cupid costume and ran away along with Bianchi, I-pin, and Lambo to hide. Tsuna, Yamamoto, Futa, and Haru split up in order to find them. Tsuna saw a crowd ahead of him. When he went there, he finds Adult I-pin and left her in his room.
Soon, Haru went to the Casino and found Adult Lambo drinking wine/milk. Haru threw Adult Lambo when Adult Lambo was just asking to drink with her to a Slot Machine. Adult Lambo reverts to Child Lambo. Yamamoto soon finds Bianchi in the Kitchen Area after smelling her Poison Cooking and was soon challenged by Bianchi. They also found Gokudera at the basement.
Tsuna and the gang soon meet up again and they haven't find Reborn, yet. Tsuna noticed a picture with a girl in it, and remembers that Reborn can impersonate anyone. After looking at the picture intensely, Reborn, as the tree in the painting, spoke which startled Tsuna. Soon, 6 men appeared and began idolizing Tsuna, which made him confused. Reborn revealed that they were also hitmen and he was the one who sent the ticket and that the boat was heading to Mafia Land. Tsuna thought that it was a place full of mafia, but finds out that it was an Amusement Park. Reborn's Pacifier suddenly glowed and a blue Pacifier also glowed.