The husband realizes something is up when he finds out she was a decent swimmer and was part of an after-hours swimming club. He turns over the house, and finds her wedding ring in the toilet.
To track her down, he finds her visually-impaired mother who is in a nursing home, and pretends to be a police officer so she will open up and tell him where she is. He finds out she is living a new life - with a new man.
He follows Laura and her beau, Ben, to a fairground and stalks them a little, before he goes to her house ... and tidies up. He sets the toast on fire to get her into the kitchen, and when Laura notices the rearranged towels and stacked tins she panics.
But it's too late - he's there, with a gun. The boyfriend calls round, but she chases him away. Using his sixth sense (and probably seeing the shadow of Martin the husband, and hearing his loud voice), Ben kicks the door down. But he's a lover, not a fighter, and is smacked unconscious.
Laura begs Martin not to kill him, which he agrees to. Then she gives him a good kicking, before trying to get away. She picks up his gun. He tries to talk her round, but she shoots him in the chest three times.
The husband's still not dead though, and manages to get the gun from her and pull the trigger himself ... but it's out of bullets.
She goes to check her new boyfriend is ok. And it all ends well now as she can fight the possible manslaughter charge in court with the husband's prints back on the gun.