It's the kings' birthday and for their royal present, they each get one wish that will come true. Right before blowing out the candles, Boomer learns that Brady has been bragging to the entire island that he is the older twin. Boomer uses his wish to find out the truth about who was born first, while Brady's wish is that Mikayla compliments him all day. Boomer travels to the center of Mt. Spew to meet with the volcano's Oracle and learn who is the older king, but the younger brother will no longer be co-king if it is known who the older brother is. So Brady, Mikayla, and Mason chase after Boomer.

Boomer and Brady discover Vault 14, a secret vault which protects Kinkow's most mysterious and powerful artifacts. They find the Duplicatus Plantus, a plant that copies anything it touches and make clone of themselves. The clones fill in for Brady and Boomer so that they can go surfing, However, clones want to replace Brady and Boomer forever.

Brady and Boomer head back to their high school prom in Chicago to flaunt their royal status. Boomer chooses a girl named Rebecca, who he thinks he once had a date with and Brady chooses Mikayla.

Brady and Boomer are just two ordinary twins. Or, so they thought. They soon learn that their parents were king and queen of a small island and they are next in line to rule. But, their distant cousin is planning to stop them from being kings.

Boomer goes to Chicago in an effort to convince Rebecca's father to let him see her after he forbids them to be together. Boz tags along and searches for a safe place to hide the Bat Medallion. Meanwhile, a menace from the past launches a surprise attack on the kings and it is revealed that Rebecca's father used to be part of the Tarantula tribe. As a result, he erases Rebecca's memory of her relationship with Boomer to keep her safe.

Boz defies Boomer's warning and goes to the Dark Side. He finds a baby and brings it home, causing the Tarantula People to threaten war because it was their baby prince.

Boomer, Boz, Mikayla, Mason, and Lanny watch Candace's show revealing the mysteries of Kinkow, causing Boz to have doubts about being Co-King. When a temple is discovered belonging to an ancient evil named Kaita the Bat Rider (whose mummy is in the possession of the Tarantula People), Candace is trapped inside and the entrance is sealed by a force field that only the Kings can get through.

The twins must save their island from an erupting volcano that they awakened. To do this they must cross into the dark side of the island and find a replacement rudy which is a task impossible to do. Lanny tells the villagers that Brady and Boomer are dead so he can become the next king.

Brady and Boomer try to recover a lost medallion that is sacred to the island but Brady, along with Mikayla, is kidnapped by the Tarantula people. Meanwhile, Lanny embarrasses Mason by showing an old workout video that features him in it.

Brady and Boomer decide that their island needs some fun, so they decide to pull pranks on everyone. No one likes their pranks, but the kings fear that bad karma is coming their way. Meanwhile, Mason gets addicted to a video game.

The kings must perform for the islanders at the Annual Harvest Festival, and Boomer can't wait to show off his singing skills. Brady knows Boomer has a horrible voice, but doesn't have the heart to tell him. When Brady's plan to protect his brother from humiliation backfires, Boomer discovers Brady is a terrific singer and arranges for Brady to sing to the kingdom.

After watching a scary movie, Brady thinks the castle is haunted. When Lanny takes him to a evil arts woman to prove to Boomer the castle is actually haunted, he brings back a ghost but not the one he intended.

While Mason is out of town, the twins hang out with a bunch of mermaids and Mikayla turns into one herself.

The Bat Medallion that Boz in Rebecca's apartment has dragged Rebecca to Kinkow. When Mikayla confiscates the Bat Medallion, Kutamungo captures her and the Bat Medallion in order to revive the Tarantula People's leader Kaita the Bat-Rider. The Kings fear of Kaita the Bat-Rider turns into revenge when they discover the evil Kaita is responsible for their father's death.

Boomer and Brady meet an odd creature in the woods named Ogie (Doug Brochu). But Brady is jelous of the Ogie and is mean to him. Brady fills a void by being Lanny's friend, but Lanny's plot is to kill him. But when Boomer is invited to a feast, he isn't going to a dinner; he is dinner—or so it seems.

Boomer and Brady join the Kinkow Fight School

The kings try to boost thier approval ratings.

Boomer teaches Boz the fine points of being a brother, but breaks one of the bro-mandments.

Boz tries to impress his ex-girlfriend with a charade of wealth. She doesn't actually care about Boz and is only there to take his made up riches.

Boz and Boomer become stuck together after Boz wishes they were closer.

When Boomer and Boz find out Lanny is mad at them, they buy him his own island. But when they learn that the source of their wealth lives on that island, a gopher that produces gold, they try to get the gopher back without Lanny finding out.

The twins must save thier island from an errupting Volcano that they awakened. To do this they must cross into the dark side of the island and find a replacement rudy which is a task imposible to do. Lanny tells the villagers that Brady and Boomer are dead so he can become the next king.

Brady and Boomer find a cute creature in the jungle and decide to keep it as a pet. But, it isn't cute for long

A pirate gives Boomer and Brady a riddle to solve that supposedly will lead them to a magical coin but the puzzle is actually a trap to ensnare the brothers so the pirate can steal the royal treasure.

Brady and Boomer want to join the Riptides, a gang famous for pulling pranks all over the island. Their final test before they will be accepted into the gang is stealing Yamakoshi; Lanny's pet fish.