The Ham-Hams don't know what a beach is and they decide to go with Laura and Kana. Once they get there the Ham-Hams have fun in the sand and Hamtaro is just about to go into the water, and then a huge (from a hamster's perspective) tidal wave comes! Hamtaro gets away in time and is safe. Laura and Kana are in a rock pool and Kana is teaching Laura how to swim. Then a storm strikes and the Ham-Hams hide under a hat. Laura and Kana's parents are looking for them and the Ham-Hams go and get the adult's attention and lead them back to Laura and Kana. After some things happen, they go home.
