Vanished Anniversary

On our 3rd anniversary, one thing (a case, something) happened.
The relationships with close friends started to fall out all of a sudden.
Everyone suspects me as a criminal, but their behavior is rather suspicious.
Collect evidence and interrogate the others.
The evidence and clues would begin to reveal the hidden truth of the disappeared anniversary.
# Play the game with 5 unique characters! Each character has different episodes. Try to guess the relationships with each other.
# There are 5 chapters and 9 different endings. Don’t worry if you fail in the middle, you can start over from the last chapter you have cleared.