Caylem was a member of an alien species living under the rule of the Mokra Order. His wife was captured while participating in an Alsaurian resistance raid on a Mokra supply center and died in prison in 2360. His daughter Ralkana later died when she tried to free her mother. Caylem subsequently refused to join the resistance and blamed himself for his wife and daughter's death.
He became delusional and believed that his wife and daughter were alive. When Starfleet Captain Kathryn Janeway was stranded on the planet and hurt, Caylem took her into his shelter and healed her neck wound. He believed that she was his daughter and 'convinced' her to help him free his wife. Janeway was unaware that Caylem's wife was dead.
When members of Janeway's crew were being held in the Mokra Order prison, Caylem helped Janeway rescue them believing that he could rescue his wife. During the rescue attempt, Caylem and Janeway ran into Augris, a high-ranking third magistrate of the Mokra Order, who revealed that the wife and daughter were dead. Caylem stabbed and killed Augris and took a phaser shot meant for Janeway. Before he died, Janeway pretended to be his daughter, assuring him that his wife was safe, and the two of them forgave Caylem for his actions. As Janeway departed the planet, Darod, a member of the Alsaurian resistance, assured Janeway that Caylem's actions would not be forgotten. (VOY: "Resistance")