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.

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.

Another suitor blasts his way into the picture, this time quite literally, as he wears an armored rocket suit.  He decided to cut straight to the point and keeps trying to snatch Lala.  Lala is able to dodge his attacks, but she finally get frustrated and fights back.  Wounded and with his armor damaged, he wander about, seeking advice from everyone, even Ren.  He comes up with a new plan to claim Lala and attempts to drug her.  

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 Roy...

One of the school prefects, Yui Kotegawa, is all about rules, discipline, and good morality.  She feels that things have gotten quite out of hand and will not tolerate anymore lewd behavior.  Yui convinces the principal to allow her to set some rules for moral behavior at school and creates an enforcement squad.  Rito comes under Yui’s special attention, as she suspects that he is the one behind the corruption of good and decent values.  As punishment, Rito is banned from speaking to any girl for two weeks!  With Lala and Ren causing all kinds of havoc, it seems almost impossible that Rito will be able to stay in line.

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.

A new rival has arrived at Sainan Private High School, Ren, one of Lala's childhood friends.  Apparently, Ren has held Lala in such high regard that he allowed himself to be her guinea pig for experiments, was proud of the memories where she made him cry, and is not the least be upset that she doesn't immediately remember him.  What is upsetting is that she still does not think of him as manly.  When they were young, Lala said that she would marry him if he became manly, but he still has a ways to go.  Not to be easily discouraged, Ren first turns to Rito for advice, then to the female students at school.  To prove his masculine strength and charm, Ren embarks upon a rigorous training regime, including fighting a gang leader and Big Foot before finally taking on a 120 km marathon.  Ren is so close to becoming the model of what all me should be like when- ... erm, gesundheit???

Momo takes to playing dating sims to figure out how to get her harem plan under way. At school, a group of students form a Momo fan club, which ends up keeping her away from Rito, who she is beginning to fall in love with.

Lala seems to be really pushing Rito's buttons at school.  All she wants to do is learn a bit more about him, but she may have gotten the wrong idea in science class when they were doing frog dissections.  Little does Rito know that he's also being studied by another alien; this one a rival for Lala's affection.  To get Rito to back off, this supposed assassin has taken Haruna hostage! Will this new guy finally get a clue that Lala is not interested in him? Can Rito save Haruna and himself from this intimidating alien assassin?

The truth needs to come out. Yami finally begins telling Rito about her past, and explains how she came to be.

Saki Tenhouin is the queen of Sainan High School.  She's the richest, the most popular, the prettiest, the vainest... you get the picture.  She's also the most jealous of Lala when she finds out that her popularity is on the rise amongst the other students (due in part to her sex appeal).  But Miss Saki will not be out done! She challenges Lala to the Miss Sainan Competition.  However, it's not a good idea to send an alien princess a challenge with an arrow stuck through it.  It's an even worse idea to try to kidnap her fiancé to ensure that she shows up.  Refusing to be made a fool of, Saki will learn Lala's secret and try to destroy her in the queen's challenge.  If she can get out of the escape pod that is...

Rito begins to get closer with Momo, which makes Mikan feel uncomfortable and misplaced. After Rin helps her during a near collapse while walking home, Mikan can no longer hold her tongue and begins to vent.

Mikan is helping Lala feel right at home with delicious home cooked meals.  Her uncle Zastin, on the other hand, is not giving Rito a favorable idea of his future as the King of Deviluke, what with the waging of intergalactic wars and all.  Rito is desperate to find a way to get out of marrying Lala without attracting her father's rage and being at fault for the destruction of the earth.  Inspired by Mikan's hot meals, Lala tries to cook for the family, but as it's her first time, the results are sub par.  Rito sees his chance and declares that he will not marry Lala unless she can cook well for him.  Oh course he's wrong to think he just off scot-free, especially when Lala returns from a cross galactic grocery shopping trip, bound and determined don a love apron from outer space.

Momo teaches Rito about the secrets of the female body and seeks to move Project Harem forward. Meanwhile, Rito learns about Ren and Run.

Lala and all of this marriage stuff are driving Rito insane! At least he can catch a few hours of sanity alone at school.  What?!?! Lala is the new transfer student?! Even though Rito implores her to keep a low profile, her antics are making her rather popular.  Even worse, Haruna has just said that she thinks Rito and Lala make a good couple! In an attempt to cheer up Rito and teach Lala more about earth culture, Mikan decides they should go on a tour of the city.  Disaster is narrowly averted following a literal wardrobe malfunction and Lala's inventions at the aquarium.  Oh, and Haruna ends up joining them on their outing which could be the beginning of a love triangle.

The vindictive Azenda the Tyrant comes to Earth to provoke Yami into fighting again. Later, Haruna and Rito have yet another awkward encounter, and Mikan and Yami grow closer...so close that Yami compromises her old assassin beliefs.