Grant Sorenson was a romantic interest for Isabel. When he arrived, she immediately took an interest to him. He died when alien crystals took over his body in an attempt to infect Laurie Dupree with a parasite that would've taken over everyone, alien or human. Agent Duff shot him when the crystals once again took over his mind whilst he was holding a gun pointed at her, Valenti, Michael, Maria and Laurie. When he died, the 'queen' of the crystals emerged from his body. The group locked it in Laurie's Grandfather's bunker. Michael then took all the air out of the bunker, which then killed it.