Sylvia Willis is a character in Season 4. She is the owner of the Allasco Vineyard and Winery in Sonoma County, California and is very well acquainted with Adrian and Trudy Monk. She is very known to greet Monk to her winery on an annual basis. When Ben Gruber visited the vineyard and introduced himself to everyone, he later went to his room where he died of a heart attack. Upon finding his body and the load of money, she, alongside Dr. David Sobin, Cal and Heidi Gefsky, Pierre LaCoste, and butler Ricardo agreed to split the money and clear any trace of Gruber being there. She and the other 5 were later arrested for covering up a crime.