Doctor Persy Trevelyan gets himself into a strange business arrangement with a man, named Blessington. Blessington is a rich businessman who is willing to invest his money in the doctor's practice if he gets three-fourths of the total Trevelyan earns per day. Everything seems to go as planned but suddenly Blessington starts acting more and more weird with every passing day. He gets even to the point of accusing two of the doctor's patients of breaking into his room. Trevelyan reaches out for Holmes' help. What will the detective find out? Is there actually a good reason for the paranoid outbursts of the rich Blessington? "The Resident Patient" is a part of "The Memoirs of Sherlock Holmes".