A pair of shows that couldn't be less alike return tonight.In the Season 2 premiere of Mistresses (9 p.m., ABC/Ch. 4), Savi has a new lease on life.And in the Season 3 premiere Longmire (11 p.m., A&E), Walt deals with the aftermath of Henry's arrest.Elsewhere on TV ...The Bachelorette (7 p.m., ABC/Ch. 4): The men compete against WNBA players ... because that's the way to find true love.MasterChef (7 p.m., Fox/Ch. 13): The contestants have 90 minutes to prepare a unique dish using dessert ingredients.Whose Line Is It Anyway? (7 p.m., CW/Ch. 30): Football player Rob Gronkowski and comedian Jonathan Mangum are the guests.American Ninja Warrior (8 p.m., NBC/Ch. 5): The competition moves to Dallas.24: Live Another Day (8 p.m., Fox/Ch. 13): Jack has a plan for tracking down Margot.Beauty and the Beast (8 p.m., CW/Ch. 30): Vincent is arrested for murder.Louie (11 and 11:30 p.m., FX): Louie succumbs to Mother Nature; Louie is on the rebound.