WARNING: The following contains spoilers for Adachi & Shimamura Season 1, Episode 6, "White Album," streaming now on Funimation.
Adachi & Shimamura delicately weaves back and forth between its' co-protagonists stories, developing their personalities and feelings separately as their dynamic together slowly grows more intimate. As the girls' Christmas Day adventure approaches, Adachi is working to keep her expectations minimized, aware that Shimamura currently doesn't reciprocate her more romantic-leaning feelings. In the end, the big day brings plenty of fun, joy and a rather curious gift exchange.
Adachi wants to give a gift to Shimamura but doesn't know her interests very well -- an ongoing reminder that Shimamura still struggles to fully open up to others. But that won't stop Adachi from seeking the perfect gift, so she enlists the effervescent Hino's help. They go to the mall and pick out a special blend of green tea that Hino remembered Shimamura liking, but Adachi later spots Shimamura doing something that initially breaks her heart. She needn't have worried though -- as it turns out, great minds think alike.
Internally, Adachi remains puzzled over what exactly she feels for Shimamura. Sometimes it's love, sometimes a crush, and other times, she simply wants to be close to Shimamura without needing to define it. Having lunch with Hino and Nagafuji and seeing the way they act together -- going from natural to goofy to intimate all in one scene -- Adachi sees that undefinable quality she wants in her own future. And with the Christmas plans entirely in her hands, she can make it happen. But of course, even the best-laid plans tend to go differently than expected.
After Adachi and Hino get Shimamura's gift at the mall, the two stop off for lunch before leaving, where they spot Shimamura and Nagafuji together on their own excursion. Hino looks surprised as well, but Adachi is saddened at seeing Shimamura spending time alone with someone other than her. Adachi is at her happiest and most comfortable when she's alone with Shimamura, like they're in their own little world and nothing else matters. Seeing her share this kind of moment with Nagafuji drives Adachi's jealousy and exposes an inner possessiveness. Regardless, she's still stoked for their upcoming Christmas get-together.
Christmas day arrives and Adachi, adorably awkward as ever, is waiting at the mall and wearing her Chinese cheongsam from work because Shimamura said it was cute. First, the girls go to the arcade for competitive air hockey matches -- Adachi wins -- then grab burgers and onion rings, and even hold hands. (After Adachi gets scolded for accidentally hurting Shimamura while trying to grab her hand.) Then they sit down for the gift exchange.
A blushing Adachi knows the significance of giving a gift to someone on Christmas. She boldly hands her gift over to Shimamura, who is thrilled to get the exact kind of green tea she'd been wanting for a while. Then, to Adachi's utter elation, Shimamura has a gift for her as well. That excitement quickly and hilariously changes to confusion as Shimamura hands her... a plastic boomerang. Turns out, Shimamura and Nagafuji were on the exact same mission as Hino and Adachi at the mall that day. After putting their heads together and thinking hard about what Christmas gift Adachi would love the most, they came up with... a plastic boomerang.
On the surface, it seems a bizarre and possibly even ridiculous gift to give. But there's a correlation to Adachi and Shimamura's relationship, even if neither of them can see it. The thing about boomerangs is that no matter how far they travel, they always come back in the end. Adachi fears pushing the boundaries of her desires too far and driving Shimamura away, while Shimamura fears getting too close to others only to lose them as they drift away. Connected by this silly boomerang, it's a sign that even though they may spend time with others and have different friends, they will always find their way back to each other.
Adachi, though confounded by the gift, treasures it deeply because of who it came from. As they go outside to an open area to test out the boomerang, Adachi is having the time of her life and has one final Christmas message for Shimamura. In her head she goes and back and forth between "I love you" and "I like you," but in the end what comes out is, "I want to be your best friend." Shimamura doesn't quite understand the sentiment but is happy to go along with Adachi's motivation. Christmas may not have gone quite as either of them had planned, but both Adachi and Shimamura had a fun, joyous day while strengthening their bond even more. As far as Adachi's concerned, it's mission accomplished.