Christina DiMari bolted up the stairs with her siblings, desperate to reach the safety of the family's third-floor bathroom. She laid down next to her three sisters and her brother, all of them trying to press their bodies flat against the cold bathroom floor. They listened for their father's thudding footsteps, terrified he would burst in with his gun and threaten to shoot them, as he often did when he was drunk. Violent noise drifted up from their living room two floors below: screams and swearing, the crash of breaking glass. Two gun shots. The children trembled. Was their mother dead? Would their dad kill them next?

That was Christina's memory of the last Christmas her family would spend together. It was one of many she longed to forget. But God had a plan for Christina's life that included her past and her deepest pain.

Now 47, Christina shares her journey from fear to faith and healing in her memoir, Ocean Star (Tyndale). Back in her teen years, she decided to someday help abused children. But the teen was unsure how she'd accomplish this. Then in 2001, Christina went to her local Barnes & Noble bookstore in Louisville, in search of firsthand accounts about dysfunctional families. There were none. She immediately knew God was telling her, "You be the one to write that book you were looking for."

In Ocean Star, Christina writes candidly about her volatile childhood home. There were Mr. DiMari's regular drunken scuffles with his wife. Sometimes he hit his children—except for Christina, who was daddy's princess. In retaliation for that love, Mrs. DiMari frequently beat Christina, repeatedly striking the child with a wooden spoon until she was covered with welts and bruises. The girl wondered, Why does my mother hate me so much?

"DiMari" is a pen name Christina chose to reflect her love for the ocean. It's an Italian phrase meaning "of the sea." Growing up near the San Francisco bay, the beach provided a place to escape. "I ran to the beach, first when I was seven, then a hundred more times," she says. It also became a place to get into trouble. In her teen years, Christina regularly ditched school to go surfing with friends. She became enamored with the carefree lifestyle of hippie beach bums and began using drugs. It seemed the party would never end. But it came to a crashing halt when, just months before her high-school graduation, a friend committed suicide, another friend died from cancer, a car ran over her dog, and she was expelled from school for skipping classes.

Christina's high-school counselor encouraged her to hang on. She arranged for Christina to return to school, and created a plan for the teen to graduate on time. In return, the counselor made Christina promise to attend college. It would be a turning point in Christina's life, and in her relationship with God.

In college, she met a Christian classmate who invited her to church. Skeptical yet curious, Christina accepted. "I had always believed in God, but I didn't really understand how believing in him made all that much difference to us while we lived on earth," she says in her book. This church was unlike any of the Catholic services she'd attended as a child. It seemed the pastor was speaking directly to Christina: "Have you ever wondered if God knows who you are? Have you ever wondered if he cares about what happens to you?"

Christina decided she wanted to experience what it meant to follow Christ. She stopped using drugs and soon transferred to Simpson College (now Simpson University), a Christian liberal arts school. She began volunteering at a children's shelter and took a mission trip to the Philippines. As Christina helped others, God began healing her heart. Memories of her past faded as life got better and better. After college she married, had two children, and happily settled down in Louisville, Kentucky. Then God unexpectedly led Christina back into her past.