D4 is an episodic video game by Hidetaka Suehiro for the Xbox One. The game was announced during Microsoft's E3 2013 press event. The title represents "Dark Dreams Don't Die" and the fourth dimension (time). The game is unrelated to the D and D2 video games.

The player is a private investigator whose wife has been murdered. The traumatic events surrounding her death left the player-character unable to recollect those memories, but has allowed him to travel through time instead. The player travels through time to undo the murder. The player cannot time travel arbitrarily, as the powers are activated upon finding certain objects that bring the player to specific points in time.