Who Threw the Barbitals in Mrs. Fletcher's Chowder?

When Amos's sister Winnie abruptly arrives in Cabot Cove with the news that she left her domineering husband, Amos, Seth, and Jessica have their hands full when they arrive in town looking to bring Winnie home. Things get tricky when Jessica hosts Amos, Winnie, and their in-laws for dinner one night and Winnie's husband ends up murdered. When it looks like Winnie is the prime suspect, Jessica has to figure out who the true culprit is.