List of Sgt. Frog episodes (season 3)

In part A, the Keroro platoon opens a hamburger store. Everyone makes hamburgers of their own style, with Tamama putting a lot of sweet potato dangos in his burger, and Giroro putting gross ingredients in it, saying "If you can't even eat this, how will you survive on the battlefield?". Fuyuki and Natsumi help them too, Natsumi helps Mois with strangely selling "smiles" that give you motivation, and Fuyuki helps with burgers. However, Keroro orders new ingredients and has to pay a very huge amount of money for them. After doing that, they finally find out none of the burgers have been sold, but only the smiles have been selling, so the plan fails.

In part B, Momoka orders her squad to find the "Legendary blossom tree", and invites Fuyuki to come watch them. She didn't invite the others, but strangely, they still came. The Legendary blossom tree has a myth, saying that two persons standing under the tree will fall in love immideatly. The plan works after having Keroro and Tamama, Mois and Giroro, and two squad members fall in love with each other accidentally. After that, Fuyuki and Momoka fall in love, when Kururu finds out that the Legendary Cherry Blossom Tree is actually the child of an alien called "Sakura Sakuura", and Momoka decides to hand the "child" over. However, with the tree gone, Fuyuki and the others become normal again, and Momoka's plan to make Fuyuki love her has failed once again.

In part A, Fuyuki and Natsumi see Keroro sneaking around on the streets. When they think he's planning something suspicious, they follow him to a dead end. Fuyuki opens a closet, and falls into a hole along with Natsumi, leading to a secret city called "Alien street". They meet Keroro and the others there. However, Pekoponians are illegal in Alien street! They disguise themselves as aliens, and explore the city.

In part B, The Keroro platoon make a test from the Keron Army, asking for their hobbies, interests, etc. When Natsumi sees Giroro doesn't have any interests, Keroro tricks him, saying Natsumi will always find him a boring man if he doesn't get a hobby, just so Keroro won't have to worry about the invasion anymore. Giroro goes to everyone to ask what their hobbies are, but they're total crap. When Natsumi hears of Giroro trying to get a hobby, she teaches him that a hobby is what interests you the most. When Giroro hears that, he realizes what interests him the most and what he really wants to do...Conquer Pekopon!

In part A, Keroro finds out Natsumi and Fuyuki have a health inspection on their school. Knowing this, the platoon invades the Health Inspection and punish the children in many ways. When Natsumi finds out, the platoon runs for it, but later gets caught by Dororo in a trap. Dororo reminds Keroro of him abusing Dororo in the Keron Army health inspection, and almost makes them suffocate, when Natsumi arrives and is about to attack. Keroro calls Dororo "most popular and loved dororo heichou", with Dororo getting all happy, not realizing he has been tricked. The platoon runs for it, with Natsumi chasing them. They get chased into the boy's changing room, where Natsumi can't go. Fuyuki accidentally gets knocked out of the door, and is seen in his underwear by all the girls on the school.

In part B, Fuyuki is still mad at Natsumi for what happened that day. Keroro realizes that if they get in a fight, Keroro might get all the blame. So he adds oil to the fire that he caused, and hosts a "sibling fight" between Natsumi and Fuyuki. At the end, when Natsumi wins, their find kind of ends, when they find out Fuyuki wasn't mad about the health examination accident, but that Natsumi threw away an occult magazine he left in the hallway. With Keroro realizing and telling it was actually him telling Giroro it was okay to burn it, they get tied to pieces of wood on a campfire and get punished.

In part A, Tamama wakes up, seeing his tail is gone. Not knowing what this means, he asks the other members of the platoon, and they explain he has become an adult. When Kururu mentions that he's now ready to "Drink, hit, and buy", Tamama explores the adult part of Alien Street to find the meaning of it. In the end, it seems that while he was asleep, the "If you can live life over again gun" fell out of a closet and fired at Tamama, making him an adult.

In part B, Fuyuki, Momoka, and the keroro platoon(except for dororo and kururu), get stranded on a deserted island. They find the platoon sitting in killer machines, and they attack. They're no match for Momoka's second personality though, and later, when Momoka has called the rescue squad, they find out that it was Kururu's island. He found the platoon knocked out, and used them as guinea pigs for his fighting machines.

Koyuki Azumaya has an eventful sleepover with Natsumi! Also, in part B, when the platoon discover that Natsumi's mum can't come and talk to the teacher about her daughter's education, they try and take the place of her mum, Aki, with hilarious results!

The platoon decide to go haunting at Natsumi and Fuyuki's school for a new invasion plan, and the ghost comes too. But when she passes through a girl called Satsuki, she takes control of her body. She doesn't know what to do, and to make it worse, there's an important swimming competition! In B, the platoon open a curry shop. The Hinatas don't think their curry is very good, but the curry is very popular, to their surprise. They discover that Kururu added something to the curry; but what?

A bored Keroro goes around looking for DVDs to watch, but there's nothing his friends have that he likes, until he spots a DVD on Kururu's desk with warning signs on it. He plays it to find that this DVD is no ordinary DVD. A Tiger Horse appears outside Keroros room whenever he opens the door. But people can come in from the outside normally. Soon everybody is trapped in the room, and nobody knows how to get out until they get out of the room by going inside of keroro's picture door which is actually exit and no Tiger horses But He realize the everyone is tiger horses. In B, Natsumi is feeling grumpy, so she disallows all sorts of things. Keroro creates some special robots to prohibit things for her, but they get out of control when Giroro paste with a weapon photo and they explode.

A god from Keron comes and chases Karara and Chiroro to Pekopon. He is angry, and the Keroro platoon try and calm him down, but their efforts make it worse. And he has been known to destroy planets in his angriness. In B, Dororo gets angry at Keroro for leaving rice in his bowl. He and Kururu team up to teach Keroro a lesson, and he experiences a rice grain's feelings about being uneaten after trying so hard to grow up into healthy rice.

Kogoro gets a visitor who wants him to find his lost cat, but he gets a space cold and ends up infecting Natsumi and Aki with his "556 Virus". Kururu learns that he has been infected with the Boss Virus who will set up base inside anyone's body and whoever gets infected afterwards will become like that person. The only way to get rid of the virus is to destroy their base inside of the original target's body.