When Dr. Zack Tyler sees Joy walk into the ER with the daughter of the man who lured Joy away from him, he's hesitant, though he's overjoyed to see her again. Out of compassion, he hires her in the ER so she can support herself and her mother, and their relationship blooms.

Meanwhile, Tressa has blackouts that grow increasingly bad. Joy and Zack rediscover their love for one another as they discover what caused the break-up. Together they work to save Tressa and uncover a rare genetic defect, a mystery that has ravaged decades of Tressa's family line.