The protagonist, Mayu DAIMON is a novice detective at the Criminal Investigation Division which deals mainly with murder cases, and soon has to handle with two corpses of old men continuously. One corpse found frozen buried in the snow and the freezing sea. With a detailed investigation she finds out a connection between the two cases which seemed to be completely different at first glance. It was just the breach to open a history of an incident which had origin back to the 1960s in Aomori Prefecture. Growing more and more as a detective, Mayu has to unravel the mystery of a case which goes beyond time and space and which ends in Hokkaido with a result that no one expected.