“Game of Thrones” kicks off its 10-episode sixth season on Sunday, April 24 at 9 p.m. on HBO. Based on the popular book series “A Song of Ice and Fire,” by George R.R. Martin, this Emmy Award-winning series chronicles an epic struggle for power in the vast and violent continent of Westeros, where summers and winters can last years. Among the returning members of the ensemble cast are Emmy and Golden Globe winner Peter Dinklage, Lena Headey, Emilia Clarke, Nikolaj Coster-Waldau, Alfie Allen, Diana Rigg, Natalie Dormer, Sophie Turner, Maisie Williams, John Bradley, Isaac Hempstead-Wright, Conleth Hill, Jonathan Pryce, and Gwendoline Christie.