EXTREME MAKEOVER: WEIGHT LOSS EDITION - "Staci" - At 32 years old, working mother Staci has been battling her weight for over 20 years. Mother to two young daughters and employed as a full-time in-home nurse, Staci also takes care of her husband, who lost the use of the left side of his body after suffering a stroke. At 456 pounds, Staci is the largest female that transformation specialist Chris Powell has worked with in his career. Committed to getting healthy, Staci goes on a year-long journey to lose half her weight and become healthier for herself and her family. "Extreme Makeover: Weight Loss Edition" airs MONDAY, JULY 18 (10:01-11:00 p.m., ET) on the ABC Television Network. (ABC/CRAIG SJODIN) CHRIS POWELL, STACI, PAULETTE LAMBERT