My Strange Hero (2018)

When Kang Bok Soo was a high school student, he was falsely accused of committing violence and kicked out of school. This was caused by his first love Son Soo Jung and a male student Oh Se Ho. Kang Bok Soo is a now an adult, but his life has not gone smoothly. To get revenge on Son Soo Jung and Oh Se Ho, he returns to the same high school as a student. The environment at the school has changed and Kang Bok Soo gets involved in unexpected cases.