Cesar Millan travels to the U.K. to help troubled dog owners in the Season 9 opener. Included: a 17-year-old gets help handling his two out-of-control Jack Russell terriers; a rescue dog's territorial behavior is addressed.

The host continues his U.K. tour in London, where he meets a pup named Herbie who must be muzzled in public because of past bad behavior. Also: a pair of German shepherd littermates have grown wild and dominant with one another; an English cocker spaniel refuses to ride in cars.

In London, the host meets two dogs that have spent most of their lives in Africa and are having trouble adjusting to their new surroundings. He also works with a Jack Russell terrier that acts up around guests, and a dog walker who struggles to control her own Patterdale-terrier mix.

Before Cesar wraps up his tour of the U.K., he helps a collie mix that's afraid to walk outside, an overly energetic Labrador and a klee kai that gets nervous around other dogs.

The host helps three New Jersey families tame their problem pooches. Included: an overly energetic mastiff mix; two misbehaving miniature dachshunds.

Robert Schwartzman, lead singer of the rock band Rooney, seeks help taming his adopted pit bull, Sandy, who's aggressive around other dogs. Also: comic-book artist Paul Lee has two adopted Boston terriers that don't get along.

Three playmates need help this week. Miss Nov 2010, Shera Bechard's dog Willa is bullying Hugh Hefner's Charlie. Miss Feb 2010, Heather Rae Young's Brandy is attacking other dogs and Miss Sept 2011, Tiffany Toth's Marley is over chewing.

Standup comedians get help from Cesar this week: Paul Rodriguez's three chihuahuas, Skyler Stone's two mixes, Ralphie May and Lahna Turner's boxer and bulldog.

Daisy, a whippet mix who is blind and deaf is fearful of other normal sensed dogs. A Labradoodle is fearful of the ocean even though it lives on a boat and Piper is scared of humans, even her owners.

Cesar travels to Florida to help NASCAR drivers with their dogs: Brian Sacks' possessive pekingese, Gizmo; Greg Biffle grant recipient, Halifax Humane Society; and Kevin Harvick's snappy chihuahua.

Exercise guru Jillian Michaels seeks Cesar's help for a second time, wanting to ensure that her rescued Chihuahua won't get aggressive with her young daughter. Later, the host helps Kelsey Grammer and his wife, Kayte, potty train their pooches.

A couple worry that their Lab, who becomes aggressive around food, could hurt their 18-month-old son. The host also helps socialize a homeless woman's protective pit bull so they can move into a women's shelter.