It's roughly a year and a half after the events of Season Four, in which Norma Bates killed his mother and made it look like a suicide. He's now running the Bates Motel and seems well-adjusted. Of course, he's anything but. While on a trip to the hardware store in town to buy paint he meets the owner, a young woman who looks strikingly similar to Norma (Vera Farmiga). They start up a friendship, which becomes complicated once she becomes interested in him and it provokes undesirable emotions in him. Also, Norman discovers that her husband is cheating on her at his hotel, which a woman named Marion.
Meanwhile, Norman's brother Dylan is living happily with new wife Emma in Oregon. They just had a baby. Emma finds out on the internet that Norma had died, which prompts Dylan to take a trip back to the motel and visit his estranged brother. Norman insists everything is fine. You see, Norman continually talks to his dead mother--and even begins to dress like her. In an interesting episode we see that he even went out to a gay bar in the Norma persona and obviously hooked up with one of the patrons. There's also former Sheriff, Alex Romero, who escapes from prison with plans to kill Norman for killing the love of his life, Norma (they were married in Season Four). Perhaps the highlight of the season is an alternative time-line version of the pivotal events from the Hitchcock film with Marian Crane-which makes much more sense in the context of the television show.
This series ended on a high note. While it's much different than Anthony Perkin's character in the original movie series, Freddie Highmore's version of Norman is right-on as both creepy and sympathetic. This series is highly recommended.