Complex sentence: Four, Tris, and Caleb are given amnesty at the Factionless hideout where Tris and Caleb discover that the Factionless leader is Four's mother, Evelyn (Naomi Watts), who Four is still resentful towards for leaving him with his abusive father, Marcus.
Split into simpler sentences: Four, Tris, and Caleb are given amnesty at the Factionless hideout. There, Tris and Caleb discover that the Factionless leader is Four's mother, Evelyn (Naomi Watts), who Four is still resentful towards her for leaving him with his abusive father, Marcus.