An old case is being brought back to light thanks to a new investigation in the upcoming episode of "NCIS" season 15. Episode 7 teases a character return thanks to this investigation.

Episode 7of "NCIS" season 15 is titled "Burden of Proof," and the official synopsis reveals that a convicted criminal swears that the NCIS agency set him up for a murder that happened a decade ago. This leads to Gibbs (Mark Harmon) starting his own investigation with a new autopsy made by Ducky (David McCallum).

What makes this episode an interesting one is that the agency will have to conduct an investigation within their turf. Knowing that the case goes back years makes this all the more interesting. With an agency such as theirs, they cannot afford to make mistakes, and should the criminal prove to be right for his claims of being set up, then this would be a big fault on NCIS' part. The entire reputation of the agency is on the line with the investigation Gibbs is doing.

Then again, it is possible that the criminal is lying, perhaps in an effort to stall for time while they plan their escape? It would not be the first time the agency would be misled like this.

When the case goes back this far, then this calls for the original people who worked on the case. This is where Senior FBI Agent Fornell (Joe Spano) will come in. He served as the investigator in the original joint FBI and NCIS case 10 years ago.

Fornell's return is something many fans and longtime viewers should look forward to. His friendship with Gibbs is perhaps one of the best elements of the case. The chance to see them solve this case together will be as exciting as ever. Along with Fornell, Ducky's return, while being the more subtle one, is just as exciting.

"NCIS" season 15 airs Tuesdays at 8 p.m. EDT on CBS.