|Jump the Shark|
|Original airdate :||23 April, 2009|
|Directed by :||Phil Sgriccia|
|Written by :||Andrew Dabb|
|Preceded by :||The Monster at the End of This Book|
|Followed by :||The Rapture|
Sam and Dean are contacted by a man named Adam Milligan, claiming to be John Winchester's son and asking for help finding his missing mother. Dean is in denial that he and Sam have another brother, and suspects Adam to be a creature trying to lure the Winchesters.
Sam and Dean get a call on one of John's cellphones from a young man named Adam Milligan in Windom, Minnesota, who is looking for John and claims to be his son. Sam and Dean head to Windom and investigate the possibility that they may have another brother. Sam's research confirms that Adam exists, and John's journal reveals John took up a case in Windom in January, 1990 (nine months before Adam was born), but the following pages have been torn out.
When Sam and Dean meet Adam face-to-face, Dean is unimpressed and is convinced that Adam has to be possessed or a supernatural creature, but both the silver and the holy water which Dean discreetly tests on Adam have no effect. Sam and Dean are left to believe that Adam has to be human and is indeed John's son and their half-brother, and Adam learns the truth about who Sam and Dean are when the latter lets slip in an angry flash that they're John's sons. It is revealed that Adam was conceived shortly after Adam's mother Kate treated him on the Windom hunt, but it wasn't until Adam was twelve that he had any contact with John, and even so it was rare and little.
Adam has called for help from John, and now from Sam and Dean, because his mother is missing, having just vanished from inside her home three days ago without any sign of a break-in. When searching Kate's house, Dean finds scratch marks under her bed around an air vent, and upon looking through the vent into the house's air shafts, he finds human remains. Meanwhile, Sam finds that the case John was on in Windom in 1990 was seventeen grave robberies in the area, which stopped after John arrived, but have now started up again. The Winchesters also find that Kate isn't the only one who's vanished, and local former-cop Joe Barton has also gone missing. Dena learns at a bar from Joe's widow that as a police officer, Joe was on the grave robbery case in 1990, and helped John kill the creature behind the grave robberies.
Throughout the investigation, the Winchesters have several close brushes with the thing they're hunting, but they never manage to see it and can't work out what it is. Dean is envious of the time John spent with Adam, but recognizes that John was ultimately trying to shield Adam from the world of hunting; so Dean and Sam clash when the latter wants to train Adam as a hunter. Dean argues that Adam deserves to retain his current life and have the normality that his brothers just can't have, while Sam feels that without hunter training, Adam is nothing but defenceless meat against the supernatural things and creatures out in the world. While Sam trains Adam, Dean goes to the crypts to investigate the grave robberies.
At the crypt, Dean discovers the thing's lair deep within the crypt, where it has raided several of the caskets to eat the corpses inside and where Joe's devoured remains are, before the thing seals him in the chamber. Meanwhile back at Sam and Adam, they prepare at the house for the creature to come, but to their shock, Adam's mother comes in, looking disheveled but alive, instead. Sam yells at Adam that it's not his mother and has to be the creature, having killed her and taken its form, and Adam is torn between whether to shoot Sam or his mother as both shout opposing claims to him. Meanwhile back in the crypt, as Dean searches for a way out, he finds fresh, devoured human remains in two of the chamber's coffins - one coffin contains Kate's corpse... and the other contains Adam's. Back at the Milligan house, the being in Adam's form reveals that both he and Kate are supernatural imposters, and he turns on Sam and knocks him out.
When Sam wakes up, he's tied down to a table, and the Kate and Adam creatures are preparing to bleed and eat him alive. Sam works out that the two creatures are ghouls - supernatural creatures which are unaffected by holy water or silver, and who usually feed on corpses and can transform into the last body they fed on. The ghouls reveal that the ghoul John hunted in 1990 was their father, and so now they're seeking revenge for their father's death - their original plan was to lure in and kill John after killing the Milligans and everyone else involved in the 1990 case, but they decided after learning John was already dead that killing Sam and Dean will have to do. Dean breaks out of the crypt through the skylight, and gets back just in time to save Sam from being bled to death. Dean proceeds to kill both the ghouls; blowing the Kate-ghoul's head away, and bludgeoning the Adam-ghoul to death.
After the ghouls have been killed, Dean insists that they give the real Adam a hunter's funeral pyre, since the ghouls didn't fake the pictures or John's journal, meaning Adam was indeed their brother. As Sam and Dean watch their half-brother's funeral pyre, Dean declares that while he looked up to John and tried to be like him, he now knows that Sam is more like John than Dean will ever be - but Dean refuses to confirm whether or not he means that as a good thing.
- Jared Padalecki as Sam Winchester
- Jensen Ackles as Dean Winchester
- Jake Abel as Adam Milligan/Ghoul
- Dedee Pfeiffer as Kate Milligan/Ghoul
- Heather Feeney as Lisa Barton
- Eby Luking as Denise
- Michael Puttonen as Cemetery director
- The motel where Sam and Dean are staying, Kelsey Manor, has a picture of the late Kim Manners on a display card, which was added by the producers in honour of Kim.
- This episode's title is a reference to the phrase, "jump[ing] the shark," which refers to a stale show using radical plot devices in an unsuccessful attempt to reinvigorate the show, due to the production crew's fears that this episode would provoke mass backlash from fans for introducing a third brother.