*pops in* Ok, so I heard you guys hadn't seen any spoilers for any episodes past 8.20, which is odd since I've definitely seen them.
I don't usually come in here, so I hope this is an okay way to present the spoilers.
As always, spoilers are subject to change - nothing I post about here is written in stone, and spoilers can always end up being inaccurate or misleading when the episodes actually air.
Episode 21:
8.21 "Meltdown":
~ A man named Ben is trying to buy a ring for his girlfriend at a jewelry store, but he doesn't have enough money yet. He doesn't mind waiting a little bit longer, though - she deserves it.
~ Meanwhile, outside the jewelry store, a man covered with tattoos (Joe) sticks something into a flower pot in front of the store and heads toward a car. He settles in, watching the jewelry store in the rear view mirror. He sees a man wearing sunglasses and a man in a baseball cap (and sunglasses) enter the store - that's his cue. He drives into the center of the intersection and stops his car, getting out and lifting the hood as traffic starts to pile up in every direction. He pretends there's something wrong with the car and heads off to find a tow truck - but he just tosses the keys into a garbage can as soon as he turns the corner.
~ Inside the jewelry store, the man with the sunglasses and the man with the baseball cap knock down the security guard and fire his gun toward the ceiling. Their voices sound electronic as they tell everyone to get down on the ground. The owner, Leonard, pushes the alarm button, but the thieves don't even care. They move around the store, stealing gold jewelry and putting it into pouches sewn into the inside of their jackets.
~ When the man with the baseball cap sees Ben holding the ring he wants to buy for his girlfriend, he demands that Ben hand it over, but Ben hesitates - he doesn't want to give it up. They struggle a bit, and Ben knocks off the man's sunglasses - they look into each other's eyes, and Ben asks why the man is doing this. Ben doesn't get an answer - instead, he gets shot and is left bleeding on the ground.
~ The thieves leave the store with the jewelry as police sirens can be heard approaching - but they aren't worried. They hop on two waiting motorcycles and speed off. The 'accident' in the middle of the intersection stops the cops from being able to pursue them, and the men zip through traffic on their motorcycles.
~ The police try to pursue the thieves, but it's like they vanished into thin air - or perhaps into the back of a truck that could hide the motorcycles and allow them to escape undetected.
~ Leonard (the man who owns the jewelry store) denies being in on the heist - but Frank has trouble believing him since the thieves apparently had keys to the jewelry cases. The man shows them the security footage, hoping it will clear his name - but all they see is static. Natalia locates the object the tattooed driver (Joe) stuck in a flower pot in front of the store. It's a jamming device - there's no way they'll get any useful surveillance footage from the jewelry store.
~ When the team gets a lead, Calleigh and Tripp follow it to a garage. They find a truck with two motorcycles in the back, and Calleigh sees a bag full of diamonds in the trash. Confused, they head toward the garage - where they see Joe with his back to them, holding a gun. They hear a gunshot, and Joe hits the ground, dead.
~ When Calleigh and Frank find their unseen shooter, they recognize him: it's Jake Berkeley (Johnny Whitworth).
~ It looks like Eric is officially back at the lab. I also see Rick Stetler and Dave Benton in the spoilers.
~ Also, a bag of diamonds (presumably the ones found outside the garage) goes missing from the evidence locker at the lab.
Episode 22:
8.22 "Mommie Deadest":
~ The episode opens on a party - it's Chuck and Laura's 20th wedding anniversary, and everybody is reminiscing about how perfect their family is. Their children, Alyssa and Cody, are wandering around the party with a video camera, taping the guests on this joyous occasion.
~ Unfortunately, the perfect evening comes to a tragic end when Laura is found dead outside, next to the garage. She had the video camera with her when she died, but all the team is able to see on the tape is Laura being hit from behind and then struck repeatedly while she was on the ground. The killer stayed out of frame.
~ The team looks into the family's perfect life - and they discover that things were not so perfect after all. When they scratch the surface, they find out that Laura was not the wonderful mother she appeared to be from the outside.
~ Meanwhile, Eric is investigating the lab for Assistant State Attorney Rebecca Nevins - I believe it relates to the missing diamonds from episode 8.21. He doesn't like sneaking around, but she insists that this is necessary. Part of his investigation involves looking into the team's bank records. Walter gets upset with Eric when Rebecca confronts him about something from his past - something that Walter told Eric and no one else.
Episode 23:
8.23 [Unknown title at this point]:
~ There is a car bombing, and the police suspect that it was a deliberate assassination. The victim: Assistant State Attorney Rebecca Nevins. Eric was on his way to meet with her in her car - he narrowly avoided being caught in the blast himself.
~ The team follows the GPS coordinates from the bomber's car to Ryan's apartment. He comes in as the police are trashing the place, confused about why they are there. A uniformed officer finds a bag of diamonds (from 8.21) in the bedroom. Ryan denies stealing the diamonds - is he guilty, or is someone trying to set him up?
Dun dun duuuuuuuuun!
8.23 looks especially exciting.
That's all I have so far. According to what I've seen, Miami has 24 episodes this season, so the finale spoilers are still forthcoming.