A brand-new Monday means a new episode of The Irrational and a new case for Mercer and the team.

The Irrational has cemented itself as a case-centric procedural with little focus on the characters' personal lives.

It should not come as a surprise that The Irrational Season 1 Episode 4 focuses heavily on a case, as spoilers for the episode tease an arduous undertaking made more challenging by a complex family history.

Mercer Takes on a Kidnapping Case

Typically, Mercer gets called to a crime scene, or someone approaches them directly to take on their case.

Remember on The Irrational Season 1 Episode 1 when the governor asked Mercer for a favor or when CJ wanted help solving her supposed murder on The Irrational Season 1 Episode 2?

It is not atypical for people to ask for Mercer's help; this time, a desperate father finds Mercer and asks for help finding his daughter.

Kidnappings are a serious issue that law enforcement usually takes quick action, but if you ask Gabi Mosley of Mosley and Associates on Found, she will tell you that it is not the case when the victims look a certain way.

The police tend to think that when black children go missing, it is because they are acting out, and given a little time, they will come back.

It is dangerous rhetoric that can get someone killed, especially when the first forty-eight hours after someone is taken are critical to them being found safe, if at all.

The father seems distraught, which is understandable, and thus, Mercer agrees to take on the case.

If you've been watching The Irrational Season 1 thus far, then you know to expect twists and turns regularly, and this case is no different.

Mercer loops in Marisa and The FBI, and the first thing they do is to interview the father so that they may get a rough idea about what transpired.

The father is very forthcoming with information and points them to his daughter's boyfriend, who is also a drug dealer.

Family is complicated, which might sound cliché, but that doesn't make it less true.

In their investigation, Marisa and Mercer learn just how complicated family can be. The kidnapping case takes a different turn when they discover something.

Their case hits several snags because some things about it don't make sense, mainly because the kidnapper kidnapped someone who couldn't pay the ransom.

So they have to look into the family because its dynamics are suspicious.

They learn that the daughter's disappearance might be a family affair since everyone seems to have motives to ensure the daughter disappears.

Mercer Wants to Play Couples with Marisa

Mercer and Marisa are divorced, but their job keeps putting them in the same orbit, and if you've read our The Irrational reviews, you know that I think they should be together because they are perfect for each other.

They have supported each other through thick and thin, Mercer being the recipient of most of that support. They remained friends even after going through a nasty divorce.

They are the poster children for amicable exes.

This case sees Mercer attempt to rekindle something from the past when he asks Marisa to be a couple … I mean, to play a couple in an undercover mission.

Human psychology dictates that people tend to trust couples more than single people, especially single men.

An opportunity presents itself for Mercer to experiment.

Mercer gets an idea to go undercover in a drug buy, but since he knows how people think, he needs someone to play his spouse with, and who better than someone he was married to, and that chemistry is still there.

Kylie is the number one supporter of the couple, so she notices that Mercer is a bit enthusiastic about playing couple with Marisa, and she takes the opportunity to joke about it with him.

Getting back with Marisa won't be easy because it's much harder to get back with someone you have a history with, and Marisa has just begun a relationship with Agent Richards.

Introducing the Zero-Sum Bias Scientific Concept.

We shouldn't forget that Mercer is a professor by profession and has a duty to teach his students about human psychology.

As a result, we get to learn exciting concepts like The Barnum Effect.

This episode introduces a new phenomenon called The Zero Sum Bias.

The premise is that in a true zero-sum game, the outcome from the scores of two players is linked and should tally to 100%.

In a non-zero-sum game, one player's score is not dependent on the other player's score.

The bias comes in when someone believes that a non-zero-sum game is zero-sum.

If you didn't understand that, I also didn't at first, but luckily, there's a photo with the concept.

The photo shows Rizwan presenting in Professor Mercer's class, so maybe he will explain it better.

Scientific concepts explored in the episode are usually tied to the case the team is working on, so this one might also be linked to the missing daughter's case.

What are your expectations of the episode?

Catch it live on Monday, October 16 at 10 p.m. on NBC and our review right after.

You may watch the promo below.

Denis Kimathi was a staff writer for TV Fanatic. He has watched more dramas and comedies than he cares to remember. Catch him on social media obsessing over [excellent] past, current, and upcoming shows or going off about the politics of representation on TV. Follow him on X.