The first "Insidious" focuses on the Lambert family — Josh and Renai, as well as their three kids, Dalton, Foster, and Cali — moving into a new home. However, shortly after their arrival, not only does their son Dalton fall into a deep coma, but supernatural phenomena begin occurring with greater frequency.
Josh's mother, Lorraine (Barbara Hershey), then reveals she's been experiencing some distressing nightmares about a red demon, leading to Elise being called in. It seems Josh, much like Dalton, at one time possessed the ability to astral project and had been nearly possessed by the Bride in Black. Following these childhood incidents, Lorraine opted to have Elise hypnotize Josh so that he couldn't remember he could travel into the Further. So Josh, with Elise's guidance, must now tap back into his once-forgotten abilities and rescue his son.
This results in, as previously mentioned, Dalton being saved, but Josh finally being possessed by the Bride in Black. However, thanks to Elise's help from beyond the grave, the Bride, as well as his ghostly mother Michelle, are vanquished, ending the Lamberts' collective nightmare. Josh and Dalton are then once again hypnotized to forget in order to quell any future run-ins with the evils of the Further.
