Law & Order: Special Victims Unit S06 E14 Game

"Hope in the darkness."

The squad is at a loss on what to do with a violent homicide when Stabler's son points out that the event is straight out of a video game. Interviewing the game's creators leads them to a former employee, who then leads them (with a few other steps along the way) to a teenage couple who claim to be unable to distinguish fantasy from reality.