Kaori Fujimiya is always alone because all of her happy memories, including time spent with her friends, disappear every Monday. Deciding that he wants to be friends with her anyway, Yuuki Hase tries to get close to Kaori each week, wishing that she would one day call him "a friend."

Second-year high school student Shun Asakura has been together with Sana Wakatsuki since they were kids, and has had feelings for her for just as long. In fourth grade, Shun's family had to move, but he couldn't tell Sana how he felt before he left town. He's regretted putting a lid on his feelings for seven years since then, until he finally returns to the town where Sana lives. He resolves to tell Sana how he really feels. But there, he meets Ayumu Fujisaki, who greatly resembles him, and what he thought of himself, like an ideal version of him.

(Source: ANN)

This is a 4-koma featuring the high school kid Kei, and his childhood friend Rin, who loves paper airplanes. Kei seems to like Rin, though he's somewhat oblivious to his own feelings. With the addition of Rin's classmate Ryuusuke, who shares her love of paper airplanes, and another new character, Aoi, Kei's emotions become more and more complicated. Apparently feelings, like paper airplanes, don't fly straight.