Cesar Millan Helps Frightened Pooch on 'Leader of the Pack' Season Finale [Exclusive Video]

Former "Dog Whisperer" star Cesar Millan is wrapping up Season 1 of his Nat Geo Wild docu-series, "Leader of the Pack," by helping Sophia, a sweet dog who does fine in a pack but, unfortunately, is terrified of humans. This debilitating fear has resulted in her being a shelter dog most of her life. She now lives at a shelter that keeps approximately 500 dogs.

In this exclusive look at the season finale, Millan meets Sophia for her evaluation and rehab, and he can tell right away that she'd seek out a hiding spot the first chance she had. Millan is informed that Sophia used to stay in a small box and getting her out of it was nearly impossible; she'd even hurt herself in the process. The good news is that she doesn't bite.

[Related: Cesar Millan Reveals Suicide Attempt, Turnaround]

First test to help Sophia out of her shell, Millan says, is to give her some open space to roam off-leash, which she's not used to. Millan immediately notices that there's something wrong with her back legs, and says, "The way she was walking, her mechanics, obviously she didn't stretch enough; she didn't run enough. A dog should never be in a kennel or in a house too long, because it's important for them to go and exercise and release energy."

More bad news: No prospective dog owners have shown interest in adopting her because more outgoing and attention-seeking dogs -- especially at such a large kennel -- outshine her.

Next, Millan has Sophia meet his top dog, Junior, whom she takes to right away. It's promising that she's clearly comfortable with other dogs. The key to her rehabilitation, according to Millan, is not about sound, but about Sophia using her nose. The process to bring her in closer and help her feel safe will rely on scent, food, and rewards.

To find out if Millan helps Sophia find a happy home, tune in to the season finale of Cesar Millan's "Leader of the Pack" on Tuesday, 3/26 at 8 PM on Nat Geo Wild.