Castiel decides he wants to hunt with Sam and Dean. They take on a case involving strange (literally) cartoonish deaths, and find out that a bank robber is using an old psychic with the power to dstort reality to help him rob banks. The concept is funny, and despite it being mostly filler, it does somewhat expand Cas's story arc in him wanting redemption (as well as crank up Naomi's creepiness factor) but there are two flaws that make this episode good. The first being that the villain was a human criminal with no real power. He took control of a demented psychic, but after Sam and Cas snapped the psychic back to his senses, he killed the criminal. It's a bit of a nitpick, but usually Sam and Dean don't kill humans unless they have to. Once the psychic regained his mind, the criminal's plan was done. Over. They didn't have to kill him.
The second flaw, the flaw of every episode so far besides the werewolf ep, was the G#D-D#MN FLASHBACKS! Yes, we know that Sam had a life with a woman the past year. Please stop beating us over the head with it. Dean's flashbacks only lasted 4 episodes. Sam's took a grand total of SEVEN!I just wish that they could've done like they did in season 4 and give Sam an entire episode to flash back to his life without Dean instead of stopping an otherwise decent episode in it's tracks.