Relationships can be a killer.

At the very least, when you have a problem, talk it through. It's much easier and far less dangerous than hiring hitmen to take out your respective loved ones. There's a lesson there for all of us.

"'Till Death" took the marriage vows to heart when the machine brought up two numbers and Reese and Finch discovered that a married couple wanted to kill each other.

Mark Pellegrino, who guest starred as the husband, seems to be in everything these days. And that's a good thing. Whether he's Lucifer on Supernatural, Gavin Baker on The Closer, or least we forget, the infamous Jacob on Lost, Pellegrino nails each role.

Perhaps I would have liked to see him play an agent opposite Reese, much like Alistair in last week's "Critical," but he still did a good job at being one half of an arguing couple.

And man, could they argue! Even I was ready for Reese to just let them dangle off a roof.

Reese was in top form as always, looking ever so smooth taking down the bad guys. There's something rather fun in watching him go toe to toe with any enemy, and using a nail gun was a nice way to change it up.

As for Reese being the marriage counselor? It's a good thing Finch was there to step up before Reese decided to do anything too crazy.

In a lot of ways, Reese comes across as the ladies man, the smooth talker, the sharp dresser, so you would think that in his endless bag of tricks he'd be able to diffuse an argument. He did diffuse a bomb after all.

Yet, it was rather great seeing Finch show off his relationship skills. He may come across as less than social and more attune to computers, but his flashbacks with Grace showed why he was perfect for the situation.

From the birthday clues to their conversations, it was clear that Finch and Grace's love for each other was blossoming. These two were really making a connection, and even when Finch wanted to tell her his big secret, she told him to do it when he felt comfortable.

It's rather tragic that this hero can only see her from afar now.

Really, this episode was a great character focus on relationships.

Carter, who I've been enjoying her banter when working with Reese, has an admirer in narcotics Detective Cal Beecher. It was nice hearing Reese ask her about moving on from her husband, and Beecher seems like a great prospect. Although, my only fear is that him getting involved with her could end up getting him killed.

Even Fusco was riding the love boat, and it was rather hilarious that Reese called him out for being melodramatic and evading his calls. That, and Reese telling him that he doesn't deserve time off. Granted, who doesn't want Fusco to have his time in the sun with a pretty lady?

This was an enjoyable episode that managed to delve a bit deeper into the characters at the same time it perfectly coincided with the topic for the case of the week. And it's with those strengths, along with the stellar acting, that really does make Person of Interest continue to be a stand out show.

There's just so much to offer and clearly so much more fun to come.

Sean McKenna was a TV Fanatic Staff Writer. He retired in May of 2017. Follow him on Twitter.