S15·E18 Despair

Episode recap

Task: Write a 280-380 word episode recap for Supernatural S15E18 (Despair).
Constraint 1: Use ONLY verifiable facts from the provided SYNOPSIS and SOURCES.
Constraint 2: Do not invent/guess titles, names, dates, etc.
Constraint 3: If details are missing, omit them.
Constraint 4: Write original, neutral, encyclopedic prose in plain text.
Constraint 5: No markdown, no asterisks, no headings, no bullet points.
Constraint 6: Word count target: 280-380 words.
SYNOPSIS: "With the plan in full motion, Sam, Dean, Castiel and Jack fight for the good of the common goal."
SOURCES:
[1] Series title: Supernatural.
[2] Created by Eric Kripke. Broadcast on The WB and The CW for 15 seasons (Sept 13, 2005 - Nov 19, 2020). Characters: Sam (Jared Padalecki) and Dean (Jensen Ackles).
[3] Cast: Jared Padalecki, Jensen Ackles, Jim Beaver, Misha Collins.
[4] Plot context: Sam and Dean Winchester lost their mother to a demonic force; father raised them as hunters.
[5] Genre: Horror, drama, fantasy, fiction.
The synopsis is extremely brief: "With the plan in full motion, Sam, Dean, Castiel and Jack fight for the good of the common goal."
The sources provide general series information but almost no specific plot details for episode 15x18.
The user wants a 280-380 word recap.
Problem: There is literally only one sentence of plot information for this specific episode in the provided text.
Constraint Check: "If the synopsis is sparse, stay concise rather than guessing." "You write ONLY verifiable facts that are explicitly supported by the provided SYNOPSIS and SOURCES."
If I write 280-380 words based only on the provided text, I will be repeating the same information or providing series-level information, which might not be a "recap" of the episode, but a description of the series context.
However, the prompt asks for an "episode recap."
The synopsis says: Sam, Dean, Castiel, and Jack fight for a common goal with a plan in motion.
The sources say: The series follows Sam and Dean Winchester (played by Jared Padalecki and Jensen Ackles). It was created by Eric Kripke. It ran for 15 seasons.
I cannot invent what the "