Sometime later, Sam and Dean arrive at the crime scene, posing as FBI agents. Dean is still feeling the guilt after betraying Sam and killing Amy, so Sam picks that exact moment to thank his brother for letting her go - awkward!
Inside Hammond's apartment, Sam finds red dirt trodden into the carpet. Dean finds an AA chip - Hammond was 10 years sober - while Sam notes that he was at a place called Jane's. Sam heads to the Outreach Centre to ask about Hammond, while Dean heads to Jane's - a flower store.
It transpires that Hammond has been paying to have flowers sent to the grave of one Elisabeth Duren - a young girl tragically killed in 2001, aged 10. The brothers learn that Elisabeth was hit by Hammond's car and believe that she has become a vengeful spirit, burning her bones to put her to rest.
But elsewhere, a man named Christopher Fisher is pursued by a vicious dog. Though he reaches the refuge of a restaurant bathroom, the hound somehow gains entry and rips Fisher apart.
The next day, Sam reads a newspaper report of Fisher's death. He learns that the dead man used to run a dog-fighting operation, but later worked at an animal shelter to atone for his sins. "People change." suggests Sam, but Dean snarks: "Tell that to ghost dog."
When they inspect Fisher's body, the Winchesters find traces of red dirt and trace the soil to a nearby apple farm. But on the drive to the farm, they encounter a terrified old man - Warner.
Back at the motel, Warner confesses that he held up a liquor store when he was a young man, killing the owner and his wife. After serving a 30-year prison sentence, he was jumped in a bar - the same bar that Matthew Hammond visited - and woke up at the apple-farm, presided over by a judge.
Frustrated that he and Sam are working to save what he considers criminals and low lives, Dean storms off to the bar. Sam decides to head back to the apple farm, and when a scared Warner refuses to join him, he leaves the old man safely enshrined in a salt circle.
Warner has sketched some symbols that he saw at the farm, so Sam sends the images along to Bobby. Meanwhile, at the bar, Dean tries to drink his guilt away, but ends up flirting with an attractive blonde barmaid named Mia. You just can't restrain that Winchester charm.
As Sam explores the apple farm, he gets a call from Bobby, who has identified the symbols as signs of the Egyptian God Osiris. "He gets a hold of you, he's judge, jury and executioner," warns Bobby.
The old hunter tells Sam that Dean may be in danger from Osiris. "This guy hones in on people who feel guilty - who does that sound like to you?" he barks. Sure enough - Dean is snatched away from outside the bar.
Back at the hotel, Warner meets his end as visions of the slain store-owner and his wife appear before him. Spooked, Warner breaks the salt circle and is shot in the head.
Dean wakes and finds himself bound by chains and presided over by Osiris. But Sam emerges, insisting he should be allowed to act as Dean's attorney. Osiris agrees, then swiftly calls his first witness to the stand - Jo Harvelle.
Osiris interrogates Jo's ghost, suggesting that her relationship with Dean ultimately led to her death. But during Sam's counter-argument, Jo admits that she got into the hunting life not because of Dean, but because she idolised her late father.
Osiris calls his next witness - Sam! He reminds the younger Winchester that he was happy with Jess, until Dean dragged him back into the hunting life. As Dean thinks back on all the blood, horror and pain he has caused, Osiris asks Sam, "Don't you think that your brother dragged you back into that catastrophic mess because he'd rather damn you with him than be alone?"
Sam refutes the claim, but Osiris reveals that he is not the one that needs to be convinced. He explains, "This is solely about how Dean feels… way down deep."
Sam calls Dean to the stand and suggests that his brother had no idea that Jess would die, and that he feels sadness, rather than guilt, over Jo's death. "Is your heart heavy with guilt, or just plain heavy?" asks Sam. "The second thing," replies Dean.
But Osiris offers Dean a choice - he can end the trial as it stands, or call his last witness. Fearing that the final witness will be Amy, Dean tells Osiris to wrap up proceedings, rather than expose his secret to Sam. "I find you, Dean Winchester, guilty in your heart, and sentence you to die," declares the god.
Returning to the motel, Sam and Dean discover that Warner has been killed. Bobby calls the brothers and reveals a way to put Osiris down, at least for a couple of centuries - they need to stab him with a ram's horn.
As Sam heads out to recover a horn, Dean surrounds himself with a salt circle, but is soon confronted by Jo's ghost, now under the control of Osiris. Dean thinks that Osiris was right - he ruined her life, and Sam's, for selfish reasons.
But Jo tells Dean that he is not to blame, and that he carries around guilt that he has no need to. Her hand forced, Jo sets off the motel's gas stove - Dean is to be consumed in a fireball, as she was.
The motel room's window freezes and shatters, a gust of wind blowing in and scattering the salt circle. Jo prepares to strike Dean's lighter and envelop the room in flame, but Sam is able to find Osiris as he preys on his next victim.
The god is run through with the horn and collapses, a dried-out husk, while Jo's spirit drops the lighter and disappears.
The next day, the Winchesters share a beer and discuss recent events. Sam asks his brother who would've been the final witness at his trial, but Dean lies once more, claiming that he has no idea.
Dean is curious as to why Sam was not also put on trial, but he suggests that after his time spent being tortured in Hell, he feels like he's paid his dues. "My past is my past," says Sam/ "And I can move on with my life - hopefully."
The brothers ride on in the Impala, with Dean less than thrilled by Sam's cheery new disposition.
• "Feels wonky," notes Dean, early in this episode. "Working a regular job." - a sign of how arc-led Supernatural has become! But for this viewer's money, it made for a nice change and 'Defending Your Life' had a pleasantly old-school feel.
• While the episode's first half is dominated by an old-fashioned 'case of the week', the second boasts some strong character development for Dean.
• Throw in a well-handled return for Alona Tal's Jo and you've got what is definitely the strongest episode of the show's seventh season so far.
• But with Dean's betrayal left unexposed, will Sam ever learn the truth about Amy's death?
• Other highlights from this week's Supernatural - Dean psyching himself up for some love action outside the bar and Sam gleaning lawyering tips from The Good Wife!