Siren (2015)

Shinobu Satomi (Tori Matsuzaka) works in the Mobile Investigation Unit of The Tokyo Metropolitan Police Department. The Mobile Investigation Unit conducts the initial investigation at all crime scenes. He works with Yuki Inokuma (Fumino Kimura). They are a couple, but they keep their relationship a secret at work. They both hope to work at the #1 Investigation Station. One day, they meet beautiful Kara Tachibana at the site where a dead body was found. Kara Tachibana appears at the other crime scenes involving grotesque murders. She shows an interest in Yuki Inokuma. Shinobu Satomi thinks it's a bad sign for Yuki Inouma. To protect his girlfriend from danger, he struggles to find uncover the truth behind the serial murder cases and Kara Tachibana's identity.