A marketing and communications pro who now works as a Washington, DC tour guide, Sally was a slim, athletic child, adolescent and young adult. But serious injuries in her 20s and early 30s nearly cost her the ability to walk and forced her to spend a year in a wheelchair. This sent her into a weight-gaining spiral which has resulted in her weighing 335 lbs today. With a family history of weight-related illness and premature death, she needs to lose weight to save her life. Sally desperately wants to get back to living life to its fullest with her husband and young son. However she finds it almost impossible to balance motherhood, working, job-hunting and daily exercise. Though she says she's working out at top intensity, when she checks in with Chris, he finds something amiss. He brings in his secret weapon to help her break through her plateaus -- his wife, Heidi, also a physical trainer. Chris says that she's even tougher than he is. Can Heidi succeed in pushing Sally past what she sees as her limits?