Rito, Haruna, and Lala are moving up in the universe, when an alien prince visits and they each become Ambassadors of Peace from the Earth.  They get more than just their titles, but a challenge to compete for the title of Greatest Hunter in the Universe.  This could be a big opportunity for Rito in reaching his goal of become the greatest man, so they compete.  After an adventure filled with dinosaurs and giant gorillas, Haruna wins the title, while Rito finds a group of Amazons who want to all marry him. 

Rito is training hard to hopefully become the Greatest Man in the Universe and save his life in the process.  While out running, he bumps into Haruna walking her dog.  She becomes very supportive of Rito, even meeting up with him everyday as he runs.  Finally, Haruna asks Rito to have lunch with her by the river.  During their date, her dog falls into the water and is rescued by Rito.  Dripping wet, Haruna takes him to her house to dry his clothes.  There, Haruna trips and almost kisses a towel-clad Rito just as her sister enters the room.

Rito is about to have the worse ‘meet the parent’ experience in the whole universe! Lala’s father, King Deviluke is coming to earth to see if Rito is worthy of being his daughter’s future husband and eventual ruler of their planet.  At school, Rito meets a strange girl on the roof, who turns out to be Lala’s father testing him.  Having made a very bad first impression, it looks like Rito is about to learn about intergalactic pain, until Lala steps in.  Now, Rito is left with only one option to save himself and the earth from total destruction: become the Greatest Man in the Universe.  

The athletic festival has arrived and Rito is in the lead to making a complete fool of himself.  He’s trying everything he can think of to impress Haruna, but keeps accidentally bumping and touching her.  While Rito is pretty sure that Haruna absolutely hates him, Lala finds herself in competition with Saki, who still wants to beat her.  The only person who seems to be really enjoying themselves it the principal as he watches the female students go through bizarre and perverted contests.  

Rito encounters a golden haired girl on street.  They begin to talk and Rito buys them taiyuki when suddenly, she attacks!  It seems that both her hands and her golden locks are weapons.  Rito tries to run away, but she pursues him.  It turns out that she is an assassin, know as Golden Darkness, hired to kill him.  Zastin comes to rescue Rito, but this girl is more than he can handle.  Lala shows up, and the girl fight is on. 

Lala’s fan club president, Stella, shows up, trying to convince her to return to make an idol CD.  Stella becomes upset when she finds that Lala is engaged and refusing to go.  Rito is held responsible for this, and must find a stand in actress to pretend that she is Lala.  Rito becomes upset when Stella decides that Haruna would be the perfect double for Lala.

Rito is a shy boy just trying to get through life and pluck up the courage to confess his love to his long time school crush. Of course, the universe seems to be against him, even to the point of dropping a naked runaway alien princess named Lala quite literally into his lap and bathtub. As if things couldn't get stranger, in the suds and confusion, Rito now finds himself engaged to the girl who fell from the sky.

Mikan’s and Rito’s parents are never home, so the approaching Christmas holiday does not excite them. Lala helps fulfill a wish of Mikan’s. Rito is accidentally transported into Peke’s body, and chaos ensues during gym class. Rito pretends to be Ren’s boyfriend as a favor, but they aren’t fooling anyone.

Haruna feels self-conscious about the size of her bust but ultimately decides that the quality of her character is more important than her exterior. Haruna finds a stray dog who turns out to be Rito. Mikan and Yami switch bodies to experience each other’s abilities.

Yami falls ill with fever, and Rito rushes her to the hospital. When she recovers, Yami questions why Rito would help her since he is her target. Kyouko and Ren eat lunch together where they end up bonding and proving useful to each other. When Lala and Rito meet with Haruna, they notice something is wrong. Haruna is not acting like herself—and, as it turns out, she’s not!

Things go awry when the group visits Saki’s private beach. Lala helps Rito study for an upcoming math test, but when the day comes, he cannot remember how to solve the problems. Lala tries to win Rito’s attention, but she is not having much luck.

Rito avoids Lala while Saki daydreams of Zastin. Ren and Lala have a gas—literally! An alien skunk gas turns them both into children. Everyone prepares for Valentine’s Day, and Rito is the object of desire for many. Yui tries to find the confidence to give her chocolate to Rito.

Since Yami always wears the same clothing, Risa and Mio take her shopping. However, her new and improved wardrobe prevents her from using her weapons properly. Haruna thinks she may have a stalker. Nana and Momo go to extremes to avoid studying the Royal Lineage of Deviluke.

Rito delivers assignments to a sick Yuki who panics with a boy in her room. Frazzled and fumbling, Rito accidentally touches her breasts. Rito wears Lala’s glasses, which enable the wearer to see through people’s clothing. Saruyama falls in love with Rito, and Lala sets up a date for them.

As Rito attempts to keep Haruna away from Lala’s gadgets, they accidentally activate one and are warped to another location—naked, of course! Haruko wants to meet Saibai, as she is a fan of his manga. However, deadlines prevent Saibai’s visit, forcing Rito to impersonate him. Unaware that Rito is in the bathroom, Lala and the girls decide to bathe. An unfortunate event finds Rito in front of a group of naked and surprised girls.

Lala vows to help Haruna find love. Saruyama points out that Rito has changed since became close with Lala. An outing goes horribly wrong, and Rito chooses to give his own life for Lala and Haruna. During this time, he realizes that he loves Lala. Rito loves Lala. The problem is, he loves Haruna, too. Lala suggests that he marry them both.

Momo sneaks into Rito’s bed. Mikan, who wants to catch Momo, sneaks in as well but does not find anything. She does, however, end up staying the night. Rito and Lala pursue a drunk Celine, who spreads her pollen to Yami, which causes her to fall for Rito. Haruna cannot fight her feelings any longer, so she tells Lala that she also likes Rito.

Celine is drunk and spreads her pollen, making Saki and the others fall for Rito. Rito sets out to buy groceries and runs into Misa. After she takes him around town, he ends up not accomplishing any tasks. Momo mistakes an innocent message for something sexual and after a series of misunderstandings, Yui ends up with a nude photo of Lala.

Lala and Rito are late for school, and Lala takes the opportunity to confess her feelings for him. They use a teleportation device to get to school faster, but they arrive sans clothing!

When Jun ends up shipwrecked at sea, he suddenly finds himself at the doors of North Academia and in a fifty-man duel gauntlet to prove his worth!