Before Sam and Dean, there were their parents, John and Mary. This is the untold love story of how they met and put it all on the line to save the entire world.

John and Millie are on different pages about his new interest in hunting and Ada tries to bridge the gap. Mary follows a trail from her father that points to the disappearance of a teenage boy in Topeka. Meanwhile, Carlos has a heart to heart with Mary as Latika dives into her books to identify the monster.

When Mary's next-door neighbor mysteriously goes missing, she and John start digging into the disappearance. During their investigation, John unexpectedly reunites with someone from his past. Carlos and Ada bond as they stakeout a potential lead for the demon's partner. Meanwhile, Latika taps into old folklore passed down from her family in hopes it helps Mary and John.

After the details of a veteran's death don't add up, Carlos brings everyone in to investigate and he shares a detail about his past that makes John see him in a new light. Mary finds an unexpected ally who has been hot on the trail of this monster and Latika tries to help Mary heal and find closure with someone she lost. Meanwhile, John's habit of running headfirst into danger leaves Millie worried for her son.

Hidden secrets from Ada's past comes to light when the gang goes undercover to look into a suspicious death. Still reeling from the last Hunt, Millie asks Mary to keep an eye on John as they split off from the others to get intel on the new case. Carlos and Ada's stakeout connects the victim to the next target. Latika's research comes up with some interesting results that lead John to be Mary's lifeline out of a sticky situation.

Mary gets a call from an old family friend who's looking for some help but when the team arrives, they learn that some crucial details were left out. While Latika struggles with being a Hunter and questions her future with it, John's eagerness, and commitment to the Hunt worries Mary. Carlos finds himself in a situation he's never experienced before and doesn't know what to do with himself.

The Hunt heats up and Mary and John find trails that lead back to their fathers. Carlos helps Mary investigate where the Akrida might be hiding but they discover more than they bargained for. Meanwhile, Millie steps in to help Latika, Ada, and John to decipher notes left behind and they stumble upon a way to get some answers.

With some intense emotions still lingering after their high stakes recovery mission, Mary and John stay close to home to watch over a newly returned Samuel Campbell. When Latika and Carlos split off to investigate the death of a musician, Carlos is forced to face a part of his past he has been avoiding. Millie spends time helping Samuel recover from his injuries and learns a little more about the Men of Letters.

When Vampires make their way into Lawrence, Carlos corrals the gang to find out why. Latika's weeks of sorting through the Men of Letters clubhouse provides vital information when John gets a scary glimpse into the future and enlists Millie's help with his plan. Meanwhile, Mary struggles with the tedious balance between feelings and action when it comes to John.

While Carlos talks through a problem in his personal life, it gives Latika a new idea about how to find the Akrida Queen. Millie's new security system for the Clubhouse proves helpful when Mary and John find an unexpected guest inside. Meanwhile, Latika's idea brings her and Carlos face to face with an unexpected ally.

In the aftermath of the fight with Golem, Carlos, Mary and Latika are cleaning the clubhouse when they hear a noise from outside. They creep out to investigate and spot a figure but can't quite make it out until it turns, and they are shocked to see John standing before them, covered in blood. Meanwhile, Carlos and Latika set out in search of something important.

Mary and John's tense discussion is interrupted when Carlos and Latika arrive to discuss a mystery involving a creepy clown. Meanwhile, Ada makes an interesting discovery.

John receives a message from a mysterious stranger. Meanwhile, Carlos, Latika and Ada work together to find answers, but time is running out. Lastly, Mary and John have a warm but awkward reunion. There is a lot to unpack, but they realize this isn't the time or place.