After the Winchesters break open the Leviathan Tablet, the Prophet Kevin Tran is called. After Leviathan leader Dick Roman is killed by Dean Winchester with the help of Castiel, the King of Hell Crowley captures Kevin for his own ends. Crowley reveals to Kevin that he has found the Demon Tablet and wishes for Kevin to translate it for Crowley's own ends. Kevin tricks Crowley, kills his guards and escapes.
Following Kevin's escape and reunion with the Winchesters, he reveals that the demon tablet describes how to close the Gates of Hell forever. Crowley is able to get the tablet at Plutus's auction and later kidnaps the future Prophets and Kevin in an effort to get the tablet translated. The future Prophets and Kevin are later rescued by the Winchesters and the Seraphim Castiel, but during the rescue the tablet is broken in two with the Winchesters and Kevin getting one half and Crowley the other half.
After getting one half of the demon tablet, Kevin works on translating it and eventually learns about the three trials that when completed, will seal the Gates of Hell. Sam Winchester begins performing them, killing a hellhound and rescuing the soul of Bobby Singer and delivering it unto Heaven.
As Sam performs the Second Trial by rescuing Bobby, Crowley realizes the impact of what is happening and sends his demons out to find Kevin in one way or another to stop Kevin from translating the tablet for the Winchesters and to use the Prophet for his own purposes.
Eventually, Crowley's demons locate and capture Linda Tran, Kevin's mother. The demons are able to learn Kevin's location from Linda's smartphone and she is imprisoned with other important prisoners of Crowley's.
Having tracked Kevin to the houseboat Fizzles' Folly in Warsaw, Missouri, Crowley personally travels there to capture Kevin. As a somewhat delusional Kevin paints new warding on the houseboat windows, Crowley causes the windows to smash, breaking the warding and teleports into the boat.
Catching Kevin's attention, Crowley tells the young Prophet that he found Kevin by tracking down and torturing his mother. Finally, Crowley admits that Linda didn't give Kevin up, so he got his location off of her SmartPhone instead. However, Crowley lies and tells Kevin that he killed Linda after getting what he wanted from her. Taunting Kevin that he is just "a fleeting blip of light" while Crowley is forever, Crowley kidnaps him.
When the Winchesters return to Fizzles' Folly a short time afterwards, they find Kevin and all of his notes gone and no sign of any damage, Crowley having presumably repaired the broken windows to keep them from finding out that he captured Kevin. The Winchesters realize that Kevin either ran or was captured once more but are left with no idea of where to look for him.
Rather than torturing Kevin to get what he wants, Crowley decides to trick him instead. To this end, Crowley sets Kevin up in an illusion of Fizzles' Folly and erases his short-term memory so that Kevin remains unaware of his capture. As part of the illusion, Crowley has two demons impersonate the Winchesters on a continual basis to manipulate Kevin from behind the scenes. Its implied that the illusion is not perfect at first and that Crowley is forced to erase Kevin's short-term memory at least a few times.
After the Winchester imposters get their impression mostly right, Crowley sends them in with his half of the demon tablet and a story about them raiding one of Crowley's Earth-side operations to get it. Kevin is excited, telling the demons that with the second half of the tablet they can finally learn the Third Trial and close the Gates of Hell. The demons try to get Kevin to send them to retrieve the other half of the demon tablet, but he feels that its not necessary since he has all of his notes. The demons leave, but Kevin secretly begins to grow suspicious as their behavior is not a complete match to the Winchesters and they forgot the secret knock.
After the demons emerge from the illusion, Crowley is pleased to now know that there are three trials before the Winchesters can slam the Gates of Hell. He is also generally pleased with the demons' performances, but points out the small imperfections in their acts that could expose them and force Crowley to "scrub" Kevin's short-term memory again, something he states is dangerous.
Later, as he goes over the second half of the tablet while the "Winchesters" are with him. Kevin claims that he needs a break and some food. To further test the fake Winchesters, Kevin gives them a shopping list of things he wants and instructs them to go to a place on the other side of town that Garth says is good. They agree to do so, confirming Kevin's suspicions of them as he knows that the real Winchesters would've never done so, especially while he still has food in the fridge. Watching the events on some monitors, Crowley is amazed by the Winchester imposters' act and expresses regret that he's too busy running things not to play Dean himself.
Once the imposters have returned with his food, Kevin springs a trap on them. Claiming that the break in the tablet prevents him from seeing key writing, Kevin "agrees" that they need the other half of the tablet. Kevin pretends to give the demons the location, but in reality sends them to a warehouse where he has a devil's trap set up, trapping both imposters.
The imposter Dean calls Crowley and informs him that Kevin tricked them and sent them into "some kind of hunter mousetrap." Annoyed, Crowley departs from where he has just retrieved the Angel Tablet from Castiel to deal with the situation himself.
At the same time, the Winchesters track down the angel and Scribe of God Metatron who wrote the Word of God in the first place. During the confrontation that follows, Dean angrily tells Metatron about Kevin and how he's "dead" because Metatron wasn't there to protect him as he should have.
Crowley travels to the illusion of Fizzles' Folly where he knocks down the door and finds Kevin calmly eating his barbeque dinner. Amused, Kevin explains that he figured out Crowley's demons essentially because they were too polite. "Well I'll be the son of a whore," comments an amazed and annoyed Crowley. Kevin taunts Crowley about how the Winchesters are now up to the Third Trial and will figure it out and shut the Gates of Hell on him. Crowley claims not to be worried about this fact.
Taking Crowley's half of the demon tablet in hand, Kevin tells him "you have no idea what's on this demon tablet, all right, the power you could've gotten with this, if you weren't running around like a chicken with his head cut off." While Crowley threatens to make Kevin tell, an amused Kevin assures him that he knows that Crowley can't and that Crowley knows it too. "You know what? I've already won. I have the angel tablet, you little smudge. And I got deals and plans up the jacksie. And I don't need you!"
Crowley grabs Kevin by the throat one-handed and strangles Kevin up against the wall. As Crowley attempts to strangle Kevin to death, he is located by Metatron. Metatron burns Crowley with white light and teleports Kevin to safety.
After taking Kevin back to his hotel room, Metatron heals Kevin's injuries from Crowley's attempt to strangle him. Upon regaining consciousness, Kevin reveals that he managed to steal Crowley's half of the demon tablet before Metatron rescued him. More than that, Kevin now knows the Third Trial: to cure a demon.
Some time later, after Crowley has been captured by the Winchesters, he claims that he lied to Kevin about killing his mother when he captured Kevin. However, Kevin and Dean are left unsure if Crowley is lying or not. Months later, after becoming a ghost, Kevin learns that his mother is in fact alive and the Winchesters are able to rescue her.
- Kevin is held captive by Crowley for around a week. At the beginning of The Great Escapist, the Winchesters get a message from Kevin that he has set up to be sent automatically if he doesn't refresh a command each week.
- These events run concurrent to Crowley holding Castiel captive. As a result, Kevin's actions indirectly help Castiel kill Ion and escape as Crowley is forced to turn his attention from Castiel to Kevin.
- Its unknown what happened to Crowley's Winchester imposters after Kevin trapped them and later escaped. Its possible they were set free at a later time or Crowley killed them for their incompetence and failure.
- The illusion of Fizzles' Folly used by Crowley contains warding, a devil's trap and a squirt gun full of holy water. While the squirt gun is likely real, just not filled with holy water, the devil's trap and the warding are presumably just an illusion. Both Crowley and the Winchester imposters walk right over the devil's trap without being harmed despite all three being known to be affected by devil's traps. Notably, Kevin is able to trick the imposters into a devil's trap at another location and they are not only affected by it, but do not appear to recognize what it is beyond it being "some kind of hunter mousetrap."
- While not seen on-screen, the location Kevin was held at had angel warding protecting it. Metatron explains to Dean that he was able to get past the warding and rescue Kevin because he is the Scribe of God. As a result, Metatron was able to simply erase the angel warding.