New Emails - S4.E1

Strange emails are sent to Kwon Joo. She thinks they’re just prank emails, but soon, she realizes the emails have been forewarning her of murders. She starts to track down who sent the emails. Meanwhile, Derek Cho, a detective from the U.S., is working temporarily in Korea. He has a younger sister who has a speech impediment, but she’s abducted and in danger.