|This article belongs to the continuity of the Dark Shadows movies.|
The swimming pool at the Collinwood estate was an Olympic-sized, enclosed natatorium that had been rarely used and had fallen into grave disrepair.
In June of 1970, young David Collins was playing with a ball inside of the empty pool. He heard a strained, distant voice and scurried about to investigate. What he found was the wraith-like visage of his dead cousin, Carolyn Stoddard—now a vampire. David ran from the pool area back into the dining room at Collinwood.
At some point after this event, the staff of Collinwood refilled the pool with water, but it quickly fell into disrepair again. By the summer of 1971, the pool wasn't being used at all and the water was contaminated with black algae and grime.
Quentin Collins, possessed by the spirit of his ancestor Charles Collins, attempted to murder his wife, Tracy, by drowning her in the murky swimming pool. Believing her to be dead, he left her floating in the water. Minutes later, Alex Jenkins came along and fished Tracy’s body out of the pool. Miraculously, she was still alive.