Described by The Wrap as a thriller, the film centers on a single mother (Kathryn Hahn, Bad Words) with two kids who visit their grandparents and things go very wrong. Ed Oxenbould (Alexander and the Terrible, Horrible, No Good, Very Bad Day) plays her son, who is protective of his sister.
According to Wikipedia, “sundowning” is described as “a psychological phenomenon associated with increased confusion and restlessness in patients with some form of dementia. Most commonly associated with Alzheimer’s disease, but also found in those with mixed dementia, the term “sundowning” was coined due to the timing of the patient’s confusion.”
Shyamalan has a small crew shooting in Philadelphia and production is said to be close to a wrap. Without a distributor, I’d have to speculate Shyamalan might take the film on the festival circuit. Though, while Shyamalan’s star has definitely fallen since The Sixth Sense, a studio would be silly not to give the film a look if given the chance.