Things turn sour when an amateur improv class meet for the first time after one of the group misjudges the situation. https://shortoftheweek.com/2021/11/22/doughnut

In the summer of 1859, a widowed physician reluctantly agrees to take a recently freed slave and her mysterious Caucasian daughter on a five-day journey through the bloody West to find a distant town's Faith Healer. The woman believes her daughter is possessed. The doctor believes she simply carries The Sickness. Either way the fact remains that every living thing the girl touches mysteriously dies.