S9·E22 Stairway to Heaven

Episode recap

Task: Write a 280-380 word episode recap for Supernatural S9E22 (Stairway to Heaven).
Constraint 1: Use ONLY verifiable facts from the provided SYNOPSIS and SOURCES.
Constraint 2: Do not invent/guess titles, names, dates, counts, awards, ratings, numbers, or plot points.
Constraint 3: If a detail is not in the material, omit it.
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: "After an angel carries out a suicide attack on an ice cream shop to kill one angel from another faction, Sam and Dean investigate and discover that the target was one of Metatron's angels and that Castiel may be responsible."
SOURCES:
[1] TMDB: Series title Supernatural (2005), TV-14, Drama, Mystery, Sci-Fi & Fantasy.
[2] Wikipedia: Created by Eric Kripke. Broadcast on The WB and The CW for 15 seasons (Sept 13, 2005, to Nov 19, 2020). Follows Sam (Jared Padalecki) and Dean (Jensen Ackles) Winchester.
[3] IMDb: Cast and crew info.
[4] TMDB: Sam and Dean Winchester lost their mother to a demonic force; father raised them to hunt paranormal evil.
[5] Simple English Wikipedia: Horror, drama, fantasy, fiction series created by Eric Kripke.
Episode Title: Stairway to Heaven (from prompt).
Episode Number: S9E22 (from prompt).
Plot: An angel performs a suicide attack at an ice cream shop. The goal was to kill an angel from a different faction. Sam and Dean Winchester investigate. They find the target was an angel belonging to Metatron. They discover Castiel may be responsible.
Series Context: Supernatural is a drama, mystery, sci-fi, fantasy, horror, and fiction series created by Eric Kripke. It stars Jared Padalecki as Sam Winchester and Jensen Ackles as Dean Winchester.
The synopsis is extremely brief.
The word count requirement is 280-380 words.
Problem: If I only use the provided facts, I cannot reach 280 words without repeating myself or adding fluff, which violates the "neutral, encyclopedic prose" and "never invent or guess" rules.
Constraint Check: "If the synopsis is sparse, stay concise rather than