King Julien's submarine sinks in the ocean; Clover & Sage go on quests to test their patience; Mort leads an escape but a spy is in the midst.
Julien and his crew watch as Ned the shark explains why he needs the lemurs' help. He tells them Lord Shark has been captured, by dolphins. They explain how the dolphins wish to get rid of all sea life apart from dolphins, selling them to Russian humans. If they would rescue Lord Shark, the sharks would take them to an army of warriors not far from the area. Pancho is convinced this is a trap, but Julien ignores him and agrees to join.
Mort and the interns are escaping. However, when they surface above the tunnel, they are met by Koto and his guards. When asked why they were found so fast, the Crocodile Ambassador speaks up and explains he was a traitor. He offered Koto his kingdom's freedom in exchange for the support of his army and his daughter's hand in marriage. Mort quickly thinks of what to do now, and then punches Brodney in the gut. In his green cloud, he tells the interns to run away.
With Clover, she eagerly holds up a map, telling Sage the weapon must be through a cave. The couple enter the cave, where Clover claims she can hear something. A large swarm of bats rush towards them, and they flee. However, Sage trips over his own feet and falls, with Clover falling on top of him. Now caught in the swarm, she screams.
With Julien, the crew ride atop the sharks to where Lord Shark has been taken. They arrive at the area where the dolphins are. The dolphins are teasing Lord Shark, who is in a cage, about his parents. Julien tells the sharks he agrees that the dolphins are awful. He then tells them that to get their leader back, they will pull off a heist. However, they will need another team member.
With Mort, the interns are being captured one by one. Mort runs. Zora notices, but lets him go, blowing him a kiss. Koto asks her where he went, but Zora covers for him and tells Koto she does not know where he went. Mort continues running, only to find a strange closet. He enters, hearing his grandmother's voice. He peeps his head through a tree, and notices the world looks different. Even he looks different. His grandmother invites him to hide, but Mort, disturbed by how everything looks, runs back outside the closet. He says he now wants to fight.
In the cave, Clover shakes the bats off of herself, even spitting one out of her mouth. She calls for Sage, who she notices is tied up. He tells her that the spiders have offered to lay their eggs in his body, once they have eaten him. Annoyed, Clover unties him. She tells him they best get out before something happens, but accidentally steps on a trap. The pair plummet down a hole that opens up, engulfing them.
Julien and Maurice are on Siren Island, saying they need what is in the cave. They hop down, and suddenly the tentacle grabs Julien. When he finally stops throwing Julien around, he tells them to leave. Julien asks if he is hiding something. The tentacle bursts back out and asks if they've been talking to his father. Julien tells him he is hiding too. Tentacle says his father forced him to play sports, but what he really wanted to do was write poetry. He fled his home planet and settled on Earth. Julien says he could help prove to his father that he is not a failure, and asks if Tentacle will join his heist team.
With Mort, he prepares a large trap for the mountain lemurs. However, he ends up getting caught in the trap himself. Injured, he falls to the ground, where a bird picks him up.
With Clover and Sage, the two emerge from a crocodile's mouth. Sage optimistically thanks the crocodile for the rest, while Clover says he was trying to eat them. She pulls Sage away. In the jungle, she tells Sage she has had enough of the map, and that his guru is clearly trying to kill them. Sage tells her to be patient, and that Jarsh-Jarsh would not do that. Clover refutes this as she sees a pack of foosa in front of them.
On a beach, Julien explains to the others how they will distract the dolphins and break Lord Shark out while they are not looking. He shows them Tentacle, and they all panic.
Mort is inside a hut, and wakes up to see Xixi. She tells him she saved him, and brought him where he would be safe. She tells him she has made him a bath, and puts on music, to Mort's confusion.
In the ocean, Julien and his crew ready themselves for their rescue. Tentacle bursts out from under the sea floor, and talks to the dolphins. The dolphins insult him. Meanwhile, Julien and the others attempt to pick the lock, but fail. As the dolphins continue their taunting, Tentacle can no longer take it and lashes out. The dolphins look back to see the crew attempting to free Lord Shark. They rush to stop them.
In the hut, Xixi shows Mort her photo album, but he is disinterested. He goes to the door, only to find mountain lemurs there. Xixi too was a traitor. Mort runs away, and finds himself at the Cove of Wonders. He hides in a box, believing he has failed Julien.
With Clover and Sage, Clover has had enough. She screams at Sage until he tells her they have found the weapon. Excited, Clover asks where. Sage simply responds, "through those trees", making Clover angrier. She laughs, saying that will probably lead them into more danger, but Sage tells her that this feels different. Sighing, Clover agrees, and follows him through the trees. She is shocked to find a bright light, believing they have found the weapon.
With Julien, the group regather themselves on a beach. Tentacle apologizes for his outburst, but Julien jumps up and reveals that they did not blow their heist. Lord Shark and Pancho appear. When Maurice asks how, Julien tells him he sent Pancho on a special mission to free Lord Shark himself and replace him with a warhead from the submarine that weighs roughly the same amount. Julien, triumphant, asks for his army. The group is led to an army of Russian space monkeys, and Julien screams back angrily at the sharks.