Every summer for the past 10 years, six awestruck bakers have descended on the grounds of Grafton, the leafy and imposing Vermont estate that is not only the filming site for “Bake Week” but also the childhood home of the show’s famous host, celebrated baker Betsy Martin. The author of numerous bestselling cookbooks and hailed as “America’s Grandmother,” Betsy Martin isn’t as warm off-screen as on, though no one needs to know that but her. She has always demanded perfection and gotten it with a smile, but this year something is off. As the baking competition commences, things begin to go awry. At first, it’s merely sabotage --- sugar replaced with salt, a burner turned to high --- but when a body is discovered, everyone is a suspect.