Complex sentence: Abigail says that the nanny, Emeline Partridge, was a witch who tried to put a curse on Sally, only for the curse to misfire, trapping all of the five people who were in the elevator as ghosts, who haunt the hotel.
Split into simpler sentences: Abigail says that the nanny, Emeline Partridge, was a witch who tried to put a curse on Sally. But the curse misfired, trapping all of the five people who were in the elevator as ghosts, who haunt the hotel.