Sam and Dean must pick up the pieces after the loss of their mother, the demise of Crowley, and the death of Castiel; Jack's birth leaves the Winchester brothers with differing opinions on how to deal with a Nephilim; Mary is dragged into the breach.
Sam and Dean begin to explore what Jack is capable of doing with his powers; an unexpected visit from Donatello alerts the brothers to the fact that Jack will need more protection than they can provide.
Missouri enlists Dean and Jody to protect her granddaughter from a wraith; Sam helps Jack learn how to control his powers.
Dean and Jack investigate when a grief counselor's patients wind up dead; they are also forced to deal with unresolved grief of their own.
Sam and Dean work on a case involving the ghost of a demented doctor; they get assistance from an unexpected source; Castiel finds his way back to the Winchesters.
Castiel is reunited with Jack and together with Sam and Dean, they go to an old Western town to investigate a murder; Dean comes face to face with a famous gunslinging outlaw.
As Sam and Dean continue their search for Jack, they stumble across a familiar foe; Lucifer manages to escape Michael's grasp and finds an unlikely and mostly unwilling ally.
Feeling as if they are running out of options, Sam and Dean agree to steal a mysterious trunk belonging to a demon named Barthamus, in exchange for a locater spell they can use to track down Jack.
Desperate to prove that he is good, Jack enlists a dreamcatcher named Kaia to help him save Mary Winchester from the alternate universe.
When Sam and Dean go missing, Jody Mills calls on Claire Novak to help find the Winchesters; some women coalesce and head off on the most important hunt of their lives.
Donna calls Sam and Dean for help after her niece, Wendy, goes missing; they discover Wendy was kidnapped by a man who sells human parts to monsters in a grotesque online auction; they must save her before it is too late.
Sisters Jamie and Jennie Plum steal a powerful book of spells from the Winchester brothers; Sam and Dean get help from a powerful and surprising ally as they try to recover the book.
Sam, Dean and Castiel search for Lucifer, who is negotiating an unlikely deal with a local faith healer named Sister Jo; Asmodeus gets closer to finding Jack.
Jack and Mary escape Michael's clutches and end up finding an ally in Bobby Singer; Sam, Dean, and Castiel continue to search for a way to open a breach; one of their own may be working against them and costing them precious time.
Sam and Dean track the missing ingredient they need to rescue Mary and Jack to a black market for religious relics where everything is not always as it seems.
Sam, Dean and Castiel are transported into the animated world of Scooby Doo; they join forces with the Scooby gang to solve a ghostly mystery.
Sam and Dean's quest to save their family leads them to a Men of Letters bunker from the 1920s and a hungry god from another dimension; Ketch makes a shocking decision about Gabriel after an encounter with Asmodeus.
Things don't go as planned for Lucifer, which exasperates Jo; the return of Gabriel perplexes Sam and Castiel; Dean gets one step closer to finding Mary and Jack.
Sam and Dean must stop Rowena, who is on a deadly mission; Castiel looks to heaven to recruit angels for an impending invasion but is shocked by the things he finds.
Gabriel returns and drags Sam and Dean into his plot for revenge on the demigods who sold him to Asmodeus; Jack's inflating confidence leads to reckless decisions that could put others in harm's way.
Sam, Dean, Castiel and Gabriel must work together to bring Mary and Jack home; Rowena's encounter with Lucifer may change someone's life.
Sam and Dean devise a plan that will save innocent lives; Jack continues to wrestle with the consequences of his decisions.
Sam and Dean continue to be tested in the battle between good and evil; an impulsive decision could alter the life of one brother forever.
Exploring the internal battle between good and evil and nature and nurture.