The series finale of Bates Motel was a bloody one. Norman killed Alex after showing him where Norma was buried but it was Alex's dying words that would prove to be Norman's undoing.
Alex used his final breath to tell Norman, "You killed your own mother. You can't hide from it." And somehow the message got through because Norman admitted, "I think I did kill her." Upon having this epiphany, the imaginary version of Norma that lived in Norman's head decided to leave because as she said, "You know everything now, and there's nothing for me to protect you from."
Norman was so overwhelmed by the whole ordeal that his brain reset to when he had just moved to the Bates Motel. In fact he even called his brother Dylan and invited him over for dinner.
When Dylan came to dinner he noticed that Norma's corpse had been dressed up and placed in the at the dining room table. After having a heart to heart with Norman about how unhealthy the whole situation was, Norman attempted to stab him. So Dylan shot Norman. But it wasn't all bad for Norman, as his last thoughts were that of him returning to his Norma's loving embrace.