Complex sentence: Meanwhile, Marcie tells Jack about a recurring dream of rain turning into blood before the storm moves in on them and they go to a nearby cabin to have sex, unaware that Ned is in the upper bunk, dead from a slashed throat.
Split into simpler sentences: Meanwhile, Marcie tells Jack about a recurring dream of rain turning into blood. As the storm moves in on them, they go to a nearby cabin to have sex, unaware that Ned is in the upper bunk, dead from a slashed throat.