S10·E21 Dark Dynasty

Episode recap

Task: Write a 280-380 word episode recap for Supernatural S10E21 (Dark Dynasty).
Constraints:
Use ONLY verifiable facts from the provided SYNOPSIS and SOURCES.
No invented titles, names, dates, counts, awards, ratings, etc.
No guessing or inventing plot points.
Original, neutral, encyclopedic prose.
Plain text only (no markdown, no asterisks, no headings, no bullet points).
Word count: 280-380 words.
Synopsis:
Dean and Sam investigate a bizarre murder.
The killer has a tattoo identical to those from the Styne family.
Castiel acts as a referee.
Charlie and Rowena work together on the Book of the Damned.
Crowley discovers his mother is missing.
Crowley turns to an old enemy for help.
Sources:
Series info: Created by Eric Kripke.
Cast: Jared Padalecki (Sam), Jensen Ackles (Dean), Jim Beaver, Misha Collins (Castiel).
Genre: Drama, Mystery, Sci-Fi, Fantasy, Horror.
Premise: Sam and Dean Winchester hunt supernatural beings.
Drafting Content:
In the tenth season, episode twenty-one of Supernatural, titled Dark Dynasty, Sam and Dean Winchester investigate a bizarre murder. During their investigation, the brothers realize that the killer bears the same tattoo as those associated with the Styne family.

In a separate storyline, Castiel serves as a referee while Charlie and Rowena are forced to work together. Their collaboration involves the Book of the Damned.

Meanwhile, Crowley discovers that his mother is missing. Following this discovery, Crowley turns to an old enemy to seek assistance.
Checking Word Count:
The draft above is very short (approx 90 words). The prompt requires 280-380 words.
Problem: The provided synopsis is extremely sparse. If I strictly follow "Use only supplied facts" and "Never invent or guess... plot points," I cannot reach 280 words without repeating myself or adding fluff, which violates "neutral, encyclopedic prose."
Re-evaluating Constraints:
"If the synopsis is sparse, stay concise rather than guessing."
"Write a grounded 280-380 word episode recap..."
There is a direct conflict between the word count requirement and the instruction to not invent facts when the source is sparse.
Strategy:
I must expand on the context provided by the sources (the series overview) to bolster the word count while remaining strictly within the bounds of the provided text. I will describe the series context (creators, actors