As per the first hit on Google, Vertigo is:
"Hitchcock's romantic story of obsession, manipulation and fear. A detective is forced to retire after his fear of heights causes the death of a fellow officer and the girl he was hired to follow. He sees a double of the girl, causing him to transform her image onto the dead girl's body. This leads into a cycle of madness and lies. Madness and lies. Madness and lies. Madness and lies."