The couple performed their work at an Indian jungle, where they were greeted by a young couple--Lucy and Thomas Sprague--a pair of younger missionaries. Though Mary was cordial at first, she expressed paranoia regarding the Spragues' appearance late one night, stating to Thomas that they could end up stealing their work and mission from them. Even after the couples dine and converse together, Mary's hostility grew, especially when it came to Lucy. She even snapped at Thomas regarding him spending time with Lucy, referring to Lucy as having been sent by the Devil--a clear indication of Mary's jealousy of Lucy.
Later that evening, Mary checked to see if Thomas was asleep, and as soon as he was, Mary turned heel and planned to kill Lucy. The maniacal villainess rose from her bed and took out a scalpel from her drawer, and shortly afterwards, the evil Mary left their bedroom and entered Lucy's so she could kill her. A scuffle followed later on, with Thomas expressing shock and horror, giving the indication that Mary had succeeded in killing Lucy. However, as the episode's progression revealed, Lucy had killed Mary, as she and Thomas were planning to run away together. Lucy had anticipated Mary's heel turn and murderous attempt, and after Mary entered, Lucy took the scalpel and killed her.