Infinite Stratos

Ichika Orimura, the first male to pilot an Infinite Stratos (IS) weapon, enrolls at the all-female IS Academy, where he quickly becomes a celebrity. Adjusting to school life under the strict guidance of his older sister and former IS pilot Chifuyu, he is surprised to learn that his dorm roommate is his childhood friend and kendo prodigy, Houki Sinonono. When Ichika is elected class representative, the British aristocrat and IS ace Cecilia Alcott opposes his selection and issues an IS duel challenge to decide the position.

Ichika is given a personal IS, Byakushiki, by Chifuyu for a match against Cecilia, who pilots the sniper-focused IS Blue Tears. During training with Houki in kendo, he prepares for the battle, where he initially struggles but manages to activate Byakushiki's First Shift and wields an energy sword. However, the match ends with Cecilia declared the winner when Ichika's IS shields are completely drained.

Cecilia appoints Ichika as class representative, which upsets Houki. The next day, Ichika meets Lingyin, a new transfer student from China and his childhood friend who is also a class representative. As Cecilia and Houki grow jealous, they push Ichika hard in IS training, and tensions rise when Lingyin tries to replace Houki as Ichika's roommate. After a disagreement over their childhood promise, Lingyin challenges Ichika to an IS duel in the upcoming Inter-Class IS Tournament.

Ichika and Lingyin face off in the Inter-Class IS Tournament when their match is interrupted by a mysterious, unmanned IS drone attacking the arena. As they and Cecilia work together to defeat the drone and protect the audience, Ichika is injured. Meanwhile, Chifuyu and Maya analyze the drone and discover its IS Core is unregistered, raising questions about its origin.

Houki is given her own room by Maya, leading to a heated exchange with Ichika and a promise from him to go on a date with her if she wins the grade-level individual tournament, sparking rumors that the winner will receive a date with Ichika. A new transfer student, Charles Dunois, a French male IS pilot with striking good looks, arrives at the Academy and becomes Ichika's roommate, drawing attention from the female students. During IS practice, Chifuyu arranges a match between Lingyin and Cecilia against Maya, who defeats them using a Rafale Revive IS developed by Charles's father's company. Later, while eating lunch with Houki, Lingyin, Cecilia, and Charles, Ichika accepts food from each girl, favoring Houki's, which causes some tension among the others.

Ichika, after losing a sparring match to Charles, trains with him before Laura interrupts and challenges Ichika, which he declines. Later, he witnesses Laura pleading with Chifuyu to return to Germany, unaware that Chifuyu once forfeited a championship to rescue him. Upon returning to his dorm, Ichika discovers Charles is actually a girl and learns her true identity, as well as her role in a corporate scheme involving espionage and deception.

Houki faces mounting pressure to win the inter-class tournament after a failed attempt to ask Ichika out sparks a rumor that the winner will get to date him. Meanwhile, Laura challenges Cecilia and Lingyin to a two-on-one spar, overwhelming them until Ichika and Charles intervene. The conflict is postponed until the tournament, which is announced to be held in pairs, with Houki ultimately drawn to team up with Laura against Ichika and Charles.

Ichika and Charles face off against Laura and Houki in a battle where Laura concentrates on fighting Ichika, ignoring Houki, who is quickly defeated by Charles. Using their teamwork, Ichika and Charles exploit Laura's AIC shield, though Ichika's own shields weaken after using Yukihira. As Laura faces defeat and recalls her painful past, she enters a berserk state, transforming her IS into a powerful dark form, which Ichika, aided by Charles's remaining IS power, manages to disrupt and stop.

Houki contacts her eccentric sister Tabane, who announces she has built a personal IS named Akatsubaki for her. Meanwhile, Ichika accompanies Charlotte to the mall to buy swimsuits for a planned beach study session, unaware that Lingyin, Cecelia, and Laura are following them; Charlotte and Ichika are discovered in a dressing room by Chifuyu and Maya. At the beach, the girls attempt to spend time with Ichika during the study session, and as sunset approaches, Chifuyu discusses Tabane with Houki, predicting the arrival of the Akatsubaki IS on July 7.

Chifuyu confronts the girls after discovering them eavesdropping on her conversation with Ichika, discussing their feelings and offering guidance. The next day, Tabane presents Houki with the advanced IS Akatsubaki, but Chifuyu soon learns that the rogue IS Silver Gospel has gone out of control. After evaluating the threat, Chifuyu dispatches the group to stop it, sending Ichika and Houki to pursue it due to their superior speed.

Ichika and Houki begin their mission, but their plan is disrupted when Ichika diverts to protect an illegal fishing boat, angering Houki. After a surprise attack from the Silver Gospel leaves Ichika seriously injured, Houki is overwhelmed with guilt and considers quitting, but her friends encourage her to continue. Determined to take action, they decide to pursue the Silver Gospel despite orders to the contrary.

During a battle against the mecha Silver Gospel, Ichika experiences a dream in which a mysterious girl and a warrior woman offer him power to protect his friends. As the battle intensifies, Houki damages one of Gospel's wings, but the enemy transforms into a more powerful form with angel-like wings and overwhelms the team. Ichika awakens Houki and, now in a new powerful form, presents her with a birthday gift before they combine their efforts to defeat Gospel, with Ichika delivering the final strike. Upon returning to their hotel, Chifuyu reprimands them for disobeying orders but grants them a reward in the form of rest.

Ichika experiences a recurring prophetic dream in which the girls battle a powerful, unyielding enemy. Meanwhile, Laura and Charlotte go shopping for new outfits to prepare for a group date with Ichika and the others.

The new student council president identifies a weakness in Ichika's combat skills and takes it upon herself to help him improve.

Ichika becomes entangled in a dangerous version of the Cinderella story, pitting him against five powerful women who hold his fate in their hands.

The mysterious woman is identified as Arachne, who seeks to obtain Ichika's IS. A new and potentially overwhelming enemy emerges, posing a significant threat to the girls.

Ichika is appointed as the sole judge for a competition in which the female participants compete to provide him with the best "service," leading to a series of escalating and unconventional performances.

Ichika's Invader is experiencing technical issues, so while it undergoes repairs, Charlotte temporarily takes on the role of his guardian.

Ichika must select a partner for an upcoming tournament, leading the other girls to believe they have a chance of being chosen.

The female team discovers Ichika's choice for the tag tournament partner, which upsets them and motivates them to push their training to new limits.

A coordinated raid by five anti-IS units disrupts Ichika and the others, throwing them into chaos. During the ensuing battle, Tatenashi is knocked unconscious.

Cecilia seeks advice from her friends on improving her information system by preparing the ideal bento lunch for Ichika.

The IS class takes a relaxed field trip, during which several girls make attempts to gain Ichika's favor. As they prepare to leave, the class is unexpectedly attacked by Phantom Task at different locations.

Ichika confronts Madoka's Black Knight IS in battle, while Tatenashi duels Squall on a rooftop. Meanwhile, Chifuyu and her students find themselves trapped on a monorail that holds a time bomb.