Ameku Takao is a genius doctor with a knack for solving all kinds of difficult cases. When a man with blue blood is brought to Tenikai General Hospital—where Takao is the vice-director—after having his leg bitten off by a large beast, she starts investigating the intriguing case with the aid of her colleague, Takanashi.

Takao comes to the conclusion that the "large beast" responsible for severing the man's leg was, in fact, a Tyrannosaurus Rex. Following this shocking deduction, the case rapidly develops, and she and her crew head to the place where they hope to get answers to the remaining mystery of the victim's blue blood.