Watch Online Free on Watchseries. "The Castle" follows three siblings left to fend for themselves after their mother suddenly disappears. Connor, Jamie, and Mia try to keep their lives afloat, transforming their suburban house into a makeshift fortress as they wait for her return. Told through the eyes of wildly imaginative middle brother Connor, "The Castle" traces fraying sibling relationships, survival strategies, and the grand stories children tell each other to feel safe. A tender, soulful story about growing up too soon, and rescuing yourself before it’s too late.