Dr. Aris Thorne is an American astrophysicist. While investigating an anomaly in the fabric of time, he accidentally finds himself in the 10th century Viking Age. Found by a Viking clan, Aris struggles to communicate with them, but with the help of the Jarl's daughter, Freya, he survives and learns their language. Over time, he becomes a warrior himself and gains respect among the Vikings. Through an oracle, he learns that his sister, Elara, who has been following him, is also trapped in this time. Aris, along with a group of Viking warriors, embarks on a perilous journey to find Elara. Upon finding her, he discovers that she has been mentally damaged by the influence of temporal energy. A timekeeper spirit offers Aris the power to heal his sister and build a bridge connecting the two worlds. However, this will mean the destruction of the Viking world. Rather than destroy the new world he loves, Aris chooses to heal his sister in his own way and save his new home. Eventually, Aris and Elara adapt to Viking society and build a new life, becoming heroes who touch the history of the Vikings and write their own new legends.