Person Of Interest comes to an end with season 5's final chapter airing this Tuesday, 21 June at 10pm EST on CBS. Episode 13 is titled, Return 0, where John Reese, Harold Finch and the rest of the team will embark on a potential suicide mission to save The Machine from Samaritan.

Showrunner Jonah Nolan teased a bloody finale episode in an interview with TV Line. He also revealed that the episode was plotted out many years ago, and added, "You know, it's a bloodbath."

Nolan explained, "There have been points along the way where we've adapted, changed course, incorporated new things — Shaw was a character that we hadn't fully conceived of when we started the show — but this is the end that we always talked about, the end that's indicated in the pilot," where Finch warned Reese, "If we keep doing this, we're not going to make it".

Previously, showrunner/creators Jonathan Nolan and Greg Plageman had teased the dramatic finale in an interview with Entertainment Weekly. Plageman said, "The whole thing turns on a Fitbit."

Nolan added, "But yeah, [the finale] was a chance for us to revisit some of those relationships that we haven't gotten a chance to get to before. And there's an awful lot compressed into it, but I think it's a more emotional finale than I anticipated we would have in some ways."

Here is the official synopsis for the series finale episode:

Finch, Reese, Fusco and Shaw embark on one last mission to prevent Samaritan from destroying The Machine and cementing its hold over mankind, on the series finale of Person of Interest.

Do not miss the emotional series finale of Person Of Interest this Tuesday on CBS.