Allison was born with a litany of heart defects. With an atrial and septal defect, transposition of the great arteries and dextracardia, she was lucky to make it to her first birthday. Today, at 17, she is a high jump star for her high school track team and a normal teenager in every way. But she needs a new pulmonary valve and conduit, since she has outgrown the one put in six years ago. Because Allison has undergone several heart surgeries already in her brief life, she has built up a significant amount of scar tissue. Her aorta is pressed against her sternum, so Dr. Robert "Jake" Jaquiss will have to carefully enter her chest or risk cutting the aorta, a mistake that could cause her to bleed to death.