Castle has reached the milestone of 100 episodes and it does so in classic fashion with a Hitchcock-ian hour filled with the shows signature humor, class and hard-nosed procedural cop format. I did not get on the Castle bandwagon until after Season three but I binged on the first three seasons before the premiere of season four. By then I was fully devoted to all things “Caskett” as it was easily one of the most likable casts assembled in recent memory. To reach the century mark is a true achievement for the one-hour drama and Castle deserves the accolades for reaching such a historic accomplishment. On most shows when the two main characters get together, it can be a recipe for disaster. However when Castle and Beckett got together it just seemed very organic and normal. It was just the natural next step in their relationship and that is why I think it works so well. They are a couple to root for, and have a great supporting cast that comes through week after week. Casting really is everything in this business.Castle is laid up in his spacious loft with a busted kneecap and has a bad case of cabin fever. Missing out on investigating homicides with Beckett, Esposito and Ryan is Castle’s equivalent of forgetting to DVR your favorite TV shows. Mystery, intrigue and murder are his bread and butter, and he pouts like a nine-year old not allowed to stay up past ten o’clock. Wheeling around the apartment, it’s hard not to think of Jimmy Stewart in the Hitchcock classic Rear Window (and if you have not seen Rear Window then we are officially not friends anymore). While Beckett would like nothing more than to stay home with her sweetie, she has bad guys to bust. Castle mopes around trying to figure out what to do when he resorts to using the high-powered binoculars that Alexis bought for him. It is when he picks those up that the plot sets in motion.Castle is doubly-bummed because his birthday is coming up and he will still be in his leg cast, which is turning into a tomb for the always-on-the-go writer. When Espo and Ryan come by to pick up Beckett, Castle pleads with them to be their Charlie and the three cops can be his angels (bonus geek points to Ryan and Esposito for their Charlie’s Angels pose after this proposition). Left to his own devices, Castle resorts to using the binoculars to spy on the apartment building across the street where he sees a young couple getting it on. Ever the dirty mind, Castle is having fun as he dips his toes in the sea of voyeurism. However, while the two are canoodling in the bedroom, the husband walks in the front door and presumably yells “Honey, I’m home!”. The wife scrambles to dress and hide her boy toy under the bed and goes to greet her husband without missing a beat. Although the lover gets away, he leaves his Sinatra-like hat in the bedroom and the husband gets wise to what is going on. While the shades are closed in the bedroom, Castle witnesses the silhouettes of the couple and the wife being thrown violently against the wall. The seasoned mystery writer is convinced that he has just witnessed a murder.When he divulges what he saw to Beckett, she assures him that it is probably the pain meds playing tricks on him. But Castle is adamant that what he saw was the real deal. To prove that everything is Kosher, Beckett speaks to the woman he thinks was murdered and she is alive and well. Over the next few days the wife is nowhere to be found through the binocular lenses, and Castle’s paranoia begins to run deep. He sees the husband carrying very heavy Hefty bags out of the apartment and is convinced that he is not crazy. He also sees the man carrying a rolled up carpet which is a classic way to dispose of a body. Add that to the mysterious husband cleaning up the supposed mess with a gas mask and bleach; a great way to clean up blood. In a clear nod to Hitchcock, Castle asks Alexis to keep an eye on him as he wheels himself over to the next building to retrieve the remains of the victim’s purse. He wants proof for himself but more so to prove that he is not losing his marbles. Naturally the husband comes home and he has to hightail it out of there with just a storage locker receipt. Far from solid proof, Caskett finds that the storage locker is…empty. Well not completely empty. There is a rolled up carpet inside to which Beckett unravels to reveal…nothing. Castle has become obsessed when he witnesses the supposed murderer washing his hands of what appears to be blood. Castle adds “I caught him red-handed! Literally red-handed!” but Beckett is not buying despite the crackpot theories that have helped her solve cases in the first 99 episodes.Something fishy is going on and even I was scratching my head trying to figure out what was going on. Oh, and there was another real murder that the team was investigating at the 12th, but it only plays as a background subplot and does not really hold water to the playful main storyline. On the night of his birthday, Caskett are set to go out to a swanky dinner and they exchange a few frisky jabs at each other making you think that they could easily be a couple in the real world. To acquiesce to Castle’s paranoia, Beckett agrees to go over to the apartment and get the actual story of what is really going on. Through the binoculars Castle watches as Beckett begins to talk to the man but soon the conversation escalates into an argument and Rick’s Spidey-Sense goes off as he fears his sweetie is in grave danger. Castle calls in the cavalry and they all descend upon the apartment where all of the lights are out. When they are turned on, the truth is revealed…it is a big surprise birthday party for Castle! Well played Beckett. Martha’s acting students played their parts of husband, wife and lover and Alexis was in on it too by giving her Dad the binoculars.While his initial reaction was that of fear, once the jig was up it really hits Rick in what he has in Beckett. It is true love. There are all sorts of inside Castle jokes littered throughout the episode but I won’t spoil those for you here. Bottom line is that they really did a nice job of seamlessly using a classic film as a template for what I think is the best Detective/Cop show on TV. I only hope that, five years from now, I am reviewing the 200th episode.