Bijou's Favorite Ribbon is the 15th episode of the series and the 15th episode of Season One.
In a game of Blind Man's Bluff, Cappy takes Bijou's ribbon on accident, but Hamtaro gets the blame. To make it up to her, everyone plans a trip to Acorn Mountain (spoiled by Stan when he wanted to take Bijou there himself) and collects some acorns to help her feel better. Laura and her class go out on a field trip to the woods, and she and Kana try to get Travis to notice Laura's new ribbons.
At the Ham-Ham Clubhouse, the Ham-Hams decide to play Blind Man's Bluff. While Bijou is napping, Cappy unknowingly takes her favorite hair ribbon for Hamtaro to use as a blindfold. She wakes up furious and confronts Hamtaro, putting an end to the game. Although Hamtaro apologizes, Bijou becomes very upset with him because he didn’t realize that the ribbon he was playing with belonged to her (as she is distraught and angry that he does not return her crush on him). She bursts into tears and closes herself inside the Clubhouse, refusing to forgive him. The Ham-Hams think it's best to leave Bijou alone for a bit until she feels better. Stan invites her to Acorn Mountain, a place that he had earlier refused to reveal the location of. He then accidentally spills the beans and they decide to all go to Acorn Mountain, while Bijou stubbornly continues to sulk at the Clubhouse. After everyone leaves, a sleepy Snoozer hears Bijou crying and comforts her. He says that Hamtaro is playful and forgetful sometimes, but is kind, and never mean or selfish; he encourages Bijou to forgive Hamtaro.
Meanwhile, the Ham-Hams are at Acorn Mountain collecting acorns and having lunch. Hamtaro decides that he will collect lots of nuts for Bijou, to make her smile again. Boss has a similar idea, and competes with Hamtaro (unaware that Hamtaro is not doing this as a romantic gesture).
Heeding Snoozer’s wise words, Bijou then decides to go where the Ham-Hams are picking acorns to find Hamtaro and forgive him. When she gets there, she discovers that Hamtaro hurt his foot while picking acorns for her. Bijou comforts him, taking off her hair-ribbon to wrap his sprain.
On a school trip, the Travis doesn’t notice Laura’s hair ribbon that she wore just for him, and she is heartbroken. Later, when Laura takes off her ribbon, Travis notices it’s gone.