Makoto married his older wife, Mariko, a former colleague. They were living happily, but his boss, Oshima, who was jealous of Makoto, threatened him, saying, "The more quiet and beautiful a woman like Mariko is, the more likely she is to have an affair." Worried, Makoto gave Mariko, who still uses a flip phone, a smartphone with a location app as a present. Then, one day, while he was monitoring Mariko's movements, he saw her footsteps heading towards a love hotel district. Her footsteps continued for three hours, and she disappeared at a love hotel...