Tabby Long is a non-Christian girl in a Catholic school whose world gets turned upside down when her dad, who has never been a man of faith, experiences a miraculous healing on Good Friday. Her father's dramatic religious conversion alienates her mother, who deserts the family. In her struggle to understand what has happened to her family, Tabby follows the suggestion of her school's religion teacher, and she begins spending time reading Scripture while in Eucharistic Adoration.

Following the practice taught by Saint Ignatius of Loyola, she inserts herself into the biblical stories she reads. Through this process, she "time travels" to first-century Jerusalem, where she is Tabitha Longinus, the daughter of the centurion Gaius Cassius Longinus, who pierces the side of the crucified Jesus, incurs a spontaneous healing, and undergoes immediate conversion. Tabitha is a Gentile girl with Jewish friends and a mother who can't accept her husband's newfound (and dangerous) faith.

When her mother flees to Rome and her father retires from the army and leaves Jerusalem, Tabitha finds herself alone in the holy city, her life in jeopardy for having entered a part of the Temple that is off-limits to Gentiles. She is drawn into belief in Jesus through her friends who are close to the Apostles, even as she struggles to devise a way to save and reunite her family -- a duty that consumes her in her modern-day life as well.

Tabitha's experiences are rooted in the stories found in the first ten chapters of the Acts of the Apostles. On the last of several days of her Scripture meditations, Tabby emerges from Adoration with a newfound faith and clarity about how her family can be reunited and healed, all with the help of the Lord.