A homicide case — long forgotten after its investigator passed away — will be resurrected in the upcoming episode of "Person of Interest" season 4. 

In the 20th episode of the sci-fi crime drama, detective Joss Carter (portrayed by Taraji P. Henson) returns in a series of flashbacks to help John Reese (Jim Caviezel) solve a homicide case. The case was one that Carter left hanging when Patrick Simmons (Robert John Burke) killed her back in season 3. 

The official synopsis for the episode titled "Terra Incognita" posted by TVGuide reads: "Reese going solo on a perilous and personal journey to solve a cold homicide case Carter was never able to close. Will John be able to take care of her unfinished business?" 

The post also shared a little sneak peek of the episode's script, featuring a light exchange between Reese and Carter.

"You know the only thing worse than a stakeout?" Carter tells Reese. "Going back to the precinct at 5 a.m. to do three hours of paperwork about a stakeout." 

Reese aims to close the cold case to be able to honor his former love interest's memory, but could he really do it despite all the risks that are attached to the case? 

When Henson's character was written out of the series, the actress was cast as one of the main characters in FOX's groundbreaking hip hop musical drama, "Empire." The show is currently on hiatus after its explosive season debut, and the cast and crew are now preparing to launch its highly anticipated second season. 

Aside from Carter, another female character will be missed by the fans of "Person of Interest" in the coming episodes. Sameen Shaw (Sarah Sashi) was captured by the Samaritans at the end of episode 11 titled "If-Then-Else," but her fate has not been discussed since then. Sashi is currently in an acting break to raise her newborn twins.