The contestants begin! Poor Mike can't run, per doctor's orders, and is really disappointed. He and Ron walk together. Helen and Tara keep pace with each other. A couple of cop cars follow Ron. These folks are going to block traffic for days. As Tara and Helen approach mile four they see some friendly faces -- Helen's husband and Tara's friend Mike. The guys join them for some running. Meanwhile, Ron and Mike make it to mile four and see Max and Ron's friend Phil. Mike is overwhelmed that Max even wants to try to walk with him, and touched by the display of support. Helen's husband drops back so he has the energy to support her at the end, and she wonders if she can do it on her own. Max accompanies Mike up to mile eight, and finally admits that he's not doing so well. Mike is okay with that, and proud that Max got as far as he did. He wonders how Ron is doing and if he's going to be able to make it, and this preoccupies him for most of the marathon. Around mile five, Ron's knees give out. Dr. H. is there to give him a look-over. Ron says that in his mind he knows he can make it, but it really might just be all in his head.

As Tara hits mile 15, she sees Season 5 winner Ali Vincent. Ali runs with Tara, and says that Tara has been an inspiration to her. Tara is appreciative of the boost that this gives her. Helen is hung up on running alone for a while, but then sees Season 6 winner Michelle, who joins her for a pep talk. Helen also becomes reenergized, and feels like nothing can stop her. Tara hits mile 22 and tells herself not to stop. Mike is at mile 13, and is still miserable and pissed off that he can't run. We flash back to Mike, 17 weeks ago, saying that a marathon is an impossible task. Mike gets his boost from Season 5's Bernie, the at-home winner! He still looks pretty great. Mike tells Bernie that he'd never actually consider this completing a marathon, because he's walking. Bernie says that Mike should give himself some damn credit. He's going to finish 26.2 miles, and no one can take that away from him.