In “Thunderbolts*,” Marvel Studios assembles an unconventional team of antiheroes — Yelena Belova, Bucky Barnes, Red Guardian, Ghost, Taskmaster and John Walker. After finding themselves ensnared in a death trap set by Valentina Allegra de Fontaine, these disillusioned castoffs must embark on a dangerous mission that will force them to confront the darkest corners of their pasts. Will this dysfunctional group tear themselves apart, or find redemption and unite as something much more before it’s too late?