Mahiru Umino is a 24-year-old office-worker with the unique ability to see people's past selves. The trauma of her own past life haunts her to this day; she was a seal who enjoyed wallowing in the Arctic snow until cruel misfortune befell her, and she was mauled to death by a polar bear.

When Ritsu Kitamura joins Mahiru's office as a new employee, he instantly becomes popular among their co-workers. But the remnant of the seal in Mahiru yelps in horror at the sight of Ritsu's past self: her mortal enemy, a polar bear. While it proves difficult for her to be apprehensive of Ritsu as he behaves more like a puppy than a menacing bear, Mahiru is not one to let her guard down. She is certain that, eventually, Ritsu will let his true self slip—that of a bloodthirsty predator.

In an office full of diverse reincarnations—from a raccoon dog to none other than "Demon King" Nobunaga Oda—Mahiru and Ritsu's spontaneous game of cat and mouse begins!