4th Period Mystery (korean movie)

4th Period Mystery

Also known as
The Clue / Fourth Period Murder Mystery / 4Gyoshi Churi Yeongyeok / 4th Period Murder Mystery / 第四課時

During 4th period when all the students are in gym class, top student
Jeong-hun (Yu Seung-Ho) walks into a classroom to find fellow classmate
Tae-gyu (Jo Sang-Keun) brutally murdered. Jeong-hun and Tae-gyu has had a
history of disliking one another.
Da-jeong (So-ra Kang) walks into the same classroom and discovers
Jeong-hun with blood covering his clothes standing near the murdered
body. Da-jeong is a mystery buff herself and loves to use her deductive
reasoning. She realizes that Jeong-hun is the prime suspect, but doesn't
believe that he killed Tae-gyu. There's only 40 minutes before next
period, in which all the students will come into the classroom and also
discover the dead body.
Jeong-hun and Da-jeong frantically search for the real killer before the
kill next period starts. With Da-jeong using her deductive reasonings
they get closer to finding the identity of the true killer. Jeong-hun's
best friend Do-il (Kim Dong-Beom) then takes part in finding the killer.
When the 40 minutes are almost up, they then discover a brutal new fact
to the case ...