Story continues from the Signal drama series. In 2021, a limousine taxi driver causes an accident on a highway and a high-level government official dies in the accident. Cold case investigation team, including Kento Saegusa (Kentaro Sakaguchi) and team leader Misaki Sakurai (Michiko Kichise), have doubts about the case. Meanwhile, in 2009, administrative officers die consecutively in car accidents. The police announce these deaths as accidents. Takeshi Oyama (Kazuki Kitamura) believes that these deaths were not the product of simple accidents. At 1123 PM, a walkie-talkie makes a connection between past and the present. Kento Saegusa and Takeshi Oyama face the threat of bioterrorism.