A traveling amusement park comes to town and Laura and Kana plan a trip with their younger cousin, Mimi. Sadly, Mimi finds herself not wanting to go when her parents are unable to take her due to the illness of her new baby sister, Tina. Laura and Kana still get to go and Hamtaro and Oxnard sneak along with them. When they return, they tell the ham-hams back at the clubhouse about their adventures. This makes Panda sad and angry because he knows that Mimi is upset about having missed out on the fun. The ham-hams hatch a plan to show Mimi a good time by inviting her to their Ham-Ham fun park.
