S8·E8 Hunteri Heroici

Episode recap

Task: Write a 280-380 word episode recap for Supernatural S8E8 (Hunteri Heroici).
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 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: Castiel tells Sam and Dean he has decided to become a hunter like them. Sam and Dean are not sold on the idea but agree to investigate a case Castiel found. The case involves a man whose heart literally burst through his chest. The deaths resemble cartoon deaths.
Sources:
[1] Supernatural (2005) is a TV-14 Drama, Mystery, and Sci-Fi & Fantasy series.
[2] Created by Eric Kripke. Broadcast on The WB and later The CW for 15 seasons (Sept 13, 2005, to Nov 19, 2020). Follows brothers Sam (Jared Padalecki) and Dean (Jensen Ackles).
[3] Created by Eric Kripke. Stars Jared Padalecki, Jensen Ackles, Jim Beaver, Misha Collins. Brothers follow father's footsteps as hunters fighting monsters, demons, and gods.
[4] Sam and Dean Winchester lost their mother to a demonic force. Father raised them as soldiers to kill paranormal evil.
[5] American horror, drama, fantasy, fiction series.
Note on Word Count: The synopsis is very short. The sources provide series-level information but very little episode-specific information. I must be careful not to hallucinate details to hit the word count. If I cannot reach 280 words using only the provided facts without being repetitive or adding unverified info, I must prioritize accuracy over the word count constraint, but I will try to expand using the series context provided in the sources.
Wait, the prompt says: "If the synopsis is sparse, stay concise rather than guessing." This contradicts the "280-380 word" instruction if the facts don't support it. However, as an archivist, I must follow the "ONLY verifiable facts" rule above all.
Facts available for the episode:
Castiel tells Sam and Dean he wants to be a hunter.
Sam and Dean are skeptical/not sold.
They investigate a case found by Castiel.
Case detail