Diary is an upcoming Tamil movie starring actor Arulnithi in the lead and the movie which is touted to be an investigative thriller recently had its trailer video release. The trailer showcases Arulnithi investigating a re-opened case on a series of mysterious bus accidents at a hill station. 

The movie is directed by debutant Innisai Pandiyan and also stars Pavithra Marimuthu in a pivotal role. Udhayanidhi Stalin's Red Giant Movies is distributing Diary, which is produced by S. Kathiresan of Five Star Creations. The technical crew of Diary includes Ron Ethan Yohann for music, Arvinnd Singh for cinematography and SP Raja Sethupathi for edits.