S15·E13 Destiny's Child

Episode recap

Task: Write a 280-380 word episode recap for Supernatural S15E13 (Destiny's Child).
Constraints:
Use ONLY verifiable facts from the provided SYNOPSIS and SOURCES.
No invented titles, names, dates, counts, awards, ratings, box-office, or plot points.
Omit details not in the material.
Write original, neutral, encyclopedic prose in plain text.
No markdown, no asterisks, no headings, no bullet points.
Word count target: 280-380 words.
Synopsis: Sam and Dean Winchester search for something that may give them an edge against God. This search leads them to Jo's door and to a secret that may have died with Ruby. Meanwhile, Castiel asks Jack to do the unthinkable to help the brothers in their quest.
Sources:
[1] TMDB: General info about Supernatural.
[2] IMDb: Created by Eric Kripke. Stars Jared Padalecki, Jensen Ackles, Jim Beaver, Misha Collins.
[3] Moviefone: Sam and Dean lost their mother to a demonic force; father raised them to be soldiers/hunters.
[4] Know Your Meme: American paranormal drama created by Eric Kripke. Premiered on The WB in September 2005.
[5] TV Tango: Sam and Dean travel in a vintage Chevy Impala.
Episode Specifics:
Sam and Dean Winchester are searching for an advantage against God.
The search leads them to Jo.
The search involves a secret potentially linked to Ruby.
Castiel asks Jack to perform an unthinkable act to assist the brothers.
Series Context (to fill word count if needed, but must be careful not to hallucinate):
Series title: Supernatural.
Created by: Eric Kripke.
Main characters: Sam and Dean Winchester.
Cast: Jared Padalecki, Jensen Ackles, Jim Beaver, Misha Collins.
Genre: Drama, Mystery, Sci-Fi & Fantasy, Paranormal drama.
Premise: Two brothers hunt supernatural figures like demons and ghosts.
Drafting - Attempt 1:
In the episode titled Destiny's Child, Sam and Dean Winchester engage in a search for an item or piece of information that might provide them with an advantage against God. This pursuit leads the brothers to the home of Jo, where they encounter a secret that may have died with the character Ruby. While the Winchesters continue their quest, Castiel approaches Jack with a request. Castiel asks Jack to perform an unthinkable action in order to assist the brothers with their