When all of the balls from Sportsville are mysterious vanishing when they enter the yard of the 'Nasty Neighbor', its to the Underdogs United to retrieve them from whom we now know as Waldobert Worst.
Seeing how effective Capi's inspirational speeches are, Beto tries to mimic them to get the other teammates to do his favors for him. Hearing about this, Emma, Kiko, and Gigi proceeds to teach him a lesson by making their own speeches.
Capi is enthusiastic when his soccer play gets nominated for a prestigious sports award, but when Gigi finds out that Capi accidentally "cheated", the rest of the team try their best to tell him the truth without breaking his heart.
Worst kidnaps and disguises himself as Kiko so he could take the latter's place on the Underdogs United. However, it doesn't take long for the rest of the Underdogs to notice how strange "Kiko" is acting.
Capi, Beto, and Kiko accuse each other of moving their trophies, but soon discover that the trophies are moving themselves. Turns out, Worst has replaced their regular trophies with his robots.
Learning about his teammates lucky charms leads to Kiko proclaiming that his smelly socks would be his 'lucky charm' from now on, vowing to never wash them again. Not long after, the socks get so smelly it nearly melts the stadium.
Gigi, filled with energy, decides to join another, low-rated soccer team named Team Googly Eyes. She now has to play on both teams on the same game when her assistance results in her team challenging against the Underdogs United.
In an attempt to impress his hero, the now-retired Guru, Capi plays some of his least-favorite games - which does nothing but embarrass him further. Capi must realize that trying to hard won't get his idol's attention.
Capi's rule-following leads him to blindly taking advice from Dr. Worst, a "doctor" who uses his 'influence' to try and put Capi and the rest of the Underdogs in a long-term bed rest so they don't do sports anymore.
Gigi brings home Cheeky the Chicken, a new pet who means-well but causes problems for the other Underdogs, even though they understand she doesn't mean harm.
The Underdogs United are tricked into being sponsored by KicketyKix, a shoe company that turns out to be one of Worst's evil plans, in exchange for fancy
To convince his teammates that he's not selfish, Beto takes Michelle Thorpedo out to a dance in a local swimming pool for the annual Water Prom. The rest of the Underdogs try to help him out as Beto hates getting his hair wet.
Emma initially tries to avoid her old, strict ballet coach, Katrina, after being reminded about her times as a dancer. But when faced with the most toughest opponents yet, the Underdogs United turn to Katrina for help.
As their clubhouse is getting fixed, the Underdogs United decided to stay in the house of the basketball superstar, Emil Rubberman, a friend of their's they try not to upset when they struggle adapting to his oversized home.
After Sergeant Referee is accidentally "forced" out of town, Capi insists that the Underdogs United should take over Referee's duties, as he's the only one who can maintain order in Sportsville.
Worst sends out a team of magicians to use their magic skills to thwart the Underdogs United, whom they find out that their supposed 'magic' isn't actually real.
To protect his status as the top competitor of meditation from his rival, Deep Thought Darren, Kiko teaches the Underdogs on how to retain their cool, which becomes challenging for the hyperactive Gigi.
Frustrated by the grass stain on his uniform, Beto convinces the stadium to replace the regular turf with an artificial, inadvertently putting Greta the Groundskeeper out of a job. Greta must save the day when the turf goes out of control.
Cheeky, Gigi's beloved former pet, returns and now wants to play soccer with the Underdogs United, but doesn't have the skills to do so. The Underdogs teach her how to play the sport by putting all of their efforts into it.
While planning to make a formal speech to the Strategy Club, Emma accidentally eats some seeds from a sports-ball tree which causes her body to bounce uncontrollably. Emma must remain still as to not screw up her big speech.
After attempting to destroy the Underdogs' clubhouse with a 50-foot tall, metal soccer ball, Worst ends up getting trapped in that ball with Gigi by accident. He then explains to the goalie how he got to Sportsville in the first place.
After adopting Champ, an extraordinary robot dog, Capi and the rest of the Underdogs United seek to find him a new home. They eventually decide that he should stay in their home.
Worst learns that his title as the "Laziest Loafer in Sportsville" is being "beaten" by another lazy loafer, so he assists the Underdogs United for help so he can win back his title.
A swarm of bugs evict Mike Morales and Oscar Bocadillo, the stadium's commentators, from their booths - which just so happens to be their home. The Underdogs agree to let them stay in their home until the swarm goes away.
After scoring a goal, Emma does a victory dance that becomes so popular she becomes a big star. Emma's newfound popularity overshadows Beto's established fame, which greatly upsets him. The two have to come to terms with this.
Worst creates a device that can bewilder Sergeant Referee and then tricks into changing all of the rules in Sportsville, resulting in disastrous consequences.
Worst discovers that whoever comes first in every sport is not only crowned a champion, but they also get full control over Sportsville. The Underdogs later found out and pursues the toy rabbit, knowing he's up to something.
Beto is recruited by a fashion agent who sees him as "photogenic". Following a series of photo shoots, Beto moves to Fashionville to fulfill his model life. Despite initially getting used to, he realizes that friends means more than fame.
Beto, feeling embittered about his practice at the field, goes to buy soccer cleats from a seemingly nice Worst that can make him run faster and move more effectively. But it turns out the cleats aren't what they seem on the outside.
While healing from an injury, Gigi decides to play some virtual games. She quickly becomes a rising star due to how good she is, so Worst creates a device that makes her addicted to games, so much so that she can never stop playing.
Following a humiliating defeat in the salon, Worst tries to get Igor the Kid banished from Sportsville by arguing that chess isn't really a sport. This causes a mass debate in the city - a debate that can only be resolved by chess.
Fed-up with Worst's usual plans, the citizens of Sportsville try to kick him out of town, but Capi convinces them that he can stay if he learns how to play sports.
A heat wave keeping everyone cooped in-doors causes the Underdogs United to become irritated with each other. They all decide to seek advice from a familiar-looking psychologist in hopes of getting their team spirit back together.
Resentful at everyone in Sportsville having trophy but him, Worst creates a device that can alter the gravity of the both the people and objects alike. He uses this to "win" at every game, to which the Underdogs must stop.
Capi, Beto, Emma, Gigi, and Worst try to break up Kiko and Chester when they found out that the latter two are secretly friends, but they soon learn that even the biggest of enemies can be the best of friends.
The Underdogs, except for Capi, decide on their elaborate plans for the break. Capi feels left out, but tries to make his own plans for his break. Soon, a similarly left-out Sergeant Referee feels Capi's plight, and the two start mingling.
Tired of the relentless competition, Kiko convinces the town to stop "keeping score", to which all agree. At first, it works out, but soon the citizens realize that not keeping score only creates further, if not more so, problems.
Gigi surprises her teammates by taking them to Planet Sports Café - while also trading their old, personal items in exchange for free food. The rest of the Underdogs agree with the restaurant's manager to serve the waiting customers.
Worst switches Sergeant Referee's official rule book with a fake one, and changes the rules so that the Underdogs United are placed on different teams with contradictory personalities.
Worst creates a recliner that can make anyone who sits on it become perpetually lazy, as a form of "training" from one of Worst's alter egos, Chad Powerhouse. Capi is among the many consumers, so the other Underdogs must save the day.
After accidentally destroying the boxing arena, which is also home to revered boxer Punchie Joe, the Underdogs United embark to find a new career for the friendly boxer.
The Underdogs usual routine of going to Sportsville when the doors close is thwarted by a rival team, who challenge the in a game of table football. Things only get messier when Worst and Sergeant Referee enter the arcade.
After a series of intense training, Kiko teaches his teammates on how to remain calm. His relaxation method, while helpful, puts the team's next victory at risk, as too much relaxation causes even more stress.
When Beto disappears, his team try to find out what he's up to. Turns out he's coaching a team with disabilities, the ParaSports Team. Beto reveals that he was hired for more than just improving their skills.
Fed up by their constant cheating, the Underdogs United go through some intense training to outwit the Super Spikes, the most dishonest team in Sportsville, in their biggest match.
After accidentally trapping her team in a locker room, Capi, Gigi, Kiko and Beto help Emma with her general knowledge quiz by substituting for her knowledge team.
When the Underdogs United face their toughest opponents yet, they turn for Guru for help; but they soon learn that he had taken a vow of silence and only communicates through gestures. The Underdogs only resort is through body language.
It's winter season, and everyone in Sportsville is readying for the holiday. Worst creates a batch of special Christmas sweaters that can make anyone who wears them become instantly lazy, while stealthy delivering them to the customer.
During Halloween where everyone is getting ready for trick or treat, Worst revives a terrifying team of zombies, who were formally soccer players in Sportsville, to scare away everyone citizens who lives there: The Drooling Zombies.
