Central Operator Katie Russell's inquisitive ways have just uncovered her parents' plan for her marriage to wealthy bachelor Bartholomew Foster. Her heart is unmoved, but she knows the match will bring her family status and respectability. Then Katie overhears a phone conversation that makes her uneasy and asks authorities to investigate. But the caller is nowhere to be found. Mysterious connections arise between the caller and a ship lost at sea.
Against propriety, Katie questions the new lighthouse keeper, Will Jesperson. Then a smallpox epidemic forces their quarantine in his lighthouse. Though of low social status, Will's bravery and kindness remove Katie's suspicion and win her love. Katie and Will together work to solve the mystery of the missing girl and the lost ship as God gives the couple the desire of their hearts.