The story centers on Ayame and Tsubaki, who are researchers at a lab in the biology department of T University. Ayame is a “returnee,” someone who lived abroad for a while and then returned to Japan. He does things at his own pace and is a “dinosaur otaku,” and Tsubaki is his older colleague who is an enthusiast of studying the skeletons of birds and dinosaurs. The story follows their slightly strange romantic relationship.