A castle-like outpost comes under attack by a creature, named Grendel, on a nightly basis. However, it refuses to attack the border lord Hrothgar. One of the outpost's residents, Pendra, escapes the following morning but is captured by a rival siege line who intend to kill her to prevent the outpost's evil from spreading. Pendra is saved by a mysterious warrior named Beowulf and rides with him. When she realizes Beowulf is riding for the outpost, she runs back to the siege line and is killed. Beowulf meets Hrothgar, and is permitted to stay to help slay the beast. Hrothgar, his daughter Kyra, and his military leader, Roland suspect that Beowulf was sent by a rival family to avenge the death of their son Nivri, Kyra's former husband. However, Kyra's suspicions dissipate when she realizes that Beowulf can sense evil.