Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Beckett and Castle in Season 4, Episode 2: “Heroes and Villains”

Castle Season 4, Episode 2: “Heroes and Villains” starts in an alley, where a young, attractive woman in a hot red dress is being heckled by a man.

Just as things start to look serious between the two, somebody cuts off the man’s hand, and then

Cut to Richard Castle, at home, slicing an onion right down the center — which is exactly what the killer did to the man in the alley. Castle’s preparing a nice homecooked meal for Martha and Alexis, when Castle’s 16-year-old daughter makes an announcement: She’s leaving for Stanford in January.

We, like Castle, are shocked. He gets a little teary-eyed, but blames it on the onion. (Right!) Then, he gets a call from Kate Beckett because there’s ...

A Man Sliced in Two

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Beckett and Castle at the Crime Scene in Season 4, Episode 2: “Heroes and Villains”

Castle and Beckett have a quick discussion about Alexis flying the coop. Beckett very seriously tells him he should let her go, because if he holds on too tight, he’ll lose her. Um, is she talking about herself here?

Anyway, Caskett is investigating the murder in the alley, where they find that — like Castle’s onion — their victim was sliced right down the middle. With a sword. The victim? Tyler Ferris, an ex-con with a history of sexual assault.

Ferris’ mom doesn’t seem too concerned about her son’s death. But she does have some 411 on him: Ferris was recently fighting with the “mobbed up” Tony “The Butcher” Valtini over money. Butcher? Sword? Makes perfect sense!

However, when Tony’s brought in for questioning, he insists he was attacked by the same masked vigilante. Without warning, he yanks down his pants to expose an L-shaped scar.

Superheroes and comics and swords? This is all right up Castle’s alley. He doesn’t waste any time employing his comic book intellect!

Lone Vengeance

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Mike Hoover, Castle, and Beckett in Season 4, Episode 2: “Heroes and Villains”

While it all might sound a little surreal, Castle insists there’s a whole underground subculture of real-life superheroes. He's sure the superhero in question designed his costume himself drawing from Spiderman, Dead Pool and Black Panther, to name a few.

What’s more? There’s one part of the vigilante’s costume that came from a very specific limited-edition comic book, only available at one spot in the city. Guess the crew knows where to head next!

At the store, Castle’s new graphic novel, Deadly Storm, is front and center on the racks, and even though Beckett tries to say she has no plans to read Castle’s latest work, the comic book employee outs her as being on a pre-order list. Oh, Kate!

Unfortch, it turns out that the superhero’s costume isn’t some weird mash-up of other vigilantes, it’s actually an original, worn by underground comic hero Lord Vengeance. LV also wears knuckle plates that look just like “buttons” Castle saw at the crime scene.

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Beckett and Castle at the Crime Scene in Season 4, Episode 2: “Heroes and Villains”

So, they returns to the crime scene and uncover the silver knuckle plate, only to have it snatched from them by the same masked murderer/vigilante! He must hang out in this alley or something.

He speeds off before our crimefighting lovebirds can do anything to stop him. Moments later, Esposito calls with the suspect’s address. Castle and Beckett forge ahead and break into the pad, where they find the masked murderer practicing his moves.

Or so they thought. The scrawny, pallid guy they find karate-chopping in his living room doesn’t exactly look like the murdering type. In fact, he’s still geeking out, practicing moves in the interrogation room.

This guy is not the real Lone Vengeance, only a sad imitation. However, he’s not totally good for nothing: He does have some info on the actual guy.

Murder, He Wrote

Credit: Michael Desmond/ABC Photo: Alexis Castle in Episode 3.15, "The Final Nail"

Back at home, Castle’s reading a Lone Vengeance comic when Alexis walks in to talk to him about Stanford. When she divulges the classes she’ll be taking, Castle realizes they’re all economics classes — which just so happens to be her boyfriend’s major.

Um, really? We usually like to give Alexis the benefit of the doubt, but this is kinda iffy.

Disappointed with his baby girl’s lovestruck decision-making, Castle goes back to reading his comic books, when he notices one shows a man with an L-shape carved into his back side — and this comic clearly came out after Tony “the Butcher’s” run-in with the vigilante.

Conclusion? The writer of the comic book is the murderer!

The crew quickly discover their writer uses a nom de plume. Esposito does some digging and finds two morecases that became Vengeance comics afterwards. Creepy!

The only problem? Lone Vengeance never murders his victims. But murder victim Ferris' mom has more intel: Tyler had been chillin’ with a “mild-mannered” man days before his murder, but things got pretty heated between them when Tyler started screaming that he “knew the truth” about him.

Who was the guy? None other than a reporter who was at the vigilante’s crime scene — Paul Whittaker.

Writer's Block

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Paul Whittaker in Season 4, Episode 2: “Heroes and Villains”

This is kind of becoming a common theme on Castle! As a crime reporter, Whittaker became so affected by all the horrible things he witnessed that he started to act out, and then chronicle them in his comics.

When Ferris — who was a source for him as a crime reporter — threatened to reveal him as Lone Vengeance, Whittaker freaked and took him out.

Later, the crew catches up with their killer/writer/superhero at the comic book store and arrests him. But when Beckett asks why he cut off the victim’s hand after he already killed him, Whittake answers wrong.

The real killer cut off the victim’s hand before he killed him. Whittaker isn’t the killer — but he definitely knows who is!

Murder, SHE Wrote

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Castle and Beckett in Season 4, Episode 2: “Heroes and Villains”

The Castle crew catch up with the real Lone Vengeance. Castle is pretty impressed with the “superhero lair.” But what’s even more impressive is who is under the LV mask.

Not only is Lone Vengeance a woman, it’s a police officer named Hastings! As Castle so eloquently said, we “didn’t see that one coming.”

Beckett interrogates her colleague and they find out they have something big in common: Hastings dad was shot dead. Since then, she took it upon herself to fight crime.

And the only reason Whittaker covered for her is because he’s absolutely in love with her. Like Beckett to Castle, Hastings is Whittaker’s muse. So many similarities!

But there’s just one tiny issue: Hastings isn’t a murderer, either. Yep. We still haven’t found our killer!

Vengeance Is Mine

Credit: Adam Taylor and Eric McCandless/ABC Television Group © 2011 Disney Photo: Beckett in Season 4, Episode 2: “Heroes and Villains”

So if it’s not Whittaker and it’s not Hastings, who is it?  

Obviously, whoever killed Ferris that night was playing Lone Vengeance, acting as a sort of impostor. And that person must have been somehow who wanted “vengeance’ on not only Ferris, but also the real Lone Vengeance.

Who else could that be but Tony the Butcher — who had beef with Ferris and was cut up (on the butt, no less) by the real LV?

At long last, we’ve caught our criminal!

But it’s not over yet. Hastings and Beckett have a moment. Beckett delivers the most adorb message of the night to Hastings:  “You’re a good cop, and you’ve got someone who cares for you. Don’t be so driven by the past that you throw away your future.”  

Talking about yourself again, Beckett? We think yes!