The plot twist sees Gary's paranoia reach new heights after Izzy (Cherylee Houston) is targeted by yobs at a cashpoint, according to the Daily Star.
It is thought that Izzy's ordeal begins when she is mugged by the gang, who also smash her wheelchair during the attack.
When Gary (Mikey North) hears what has happened, he is stunned and apparently refuses to get Izzy's chair fixed as he does not want her to leave the house again.
A source told the newspaper: "Gary is having another breakdown and doesn't see Izzy's mugging as a random event. He thinks someone's out to kill her and thinks that if he doesn't get her chair fixed then she can't go anywhere.
"He's not doing it out of malice - in his head, he thinks he's protecting her."
Izzy is expected to eventually be rescued by her dad Owen (Ian Puleston-Davies), who is alerted to her situation when he hears her screaming for help.
Coronation Street viewers have already seen Gary grow increasingly protective over Izzy in recent weeks. His problems stem back to his horrifying experience in Afghanistan, which left him suffering from post-traumatic stress disorder.
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