The Girl’s Detective Club Is Here! (少女探偵団、始動よ！) is the third episode of the spin-off anime series Mahouka Koukou no Yuutousei. This spin-off follows the events of the main series from the perspective of the girls, especially that of Shiba Miyuki.
With the club recruitment week happening at First High School, Mitsui Honoka and Kitayama Shizuku, who are all-round outstanding students, are asked by various clubs to join. When they find themselves mobbed by club members, Akechi Eimi comes to the rescue, and the three of them become fast friends.
On the way home from school, Honoka and her friends witness Shiba Tatsuya, who recently became a member of the Public Morals Committee, being attacked by someone. Eimi decides to investigate who the attacker is, and Honoka and Shizuku get pulled into Eimi’s investigation.
Shiba Miyuki greets Mitsui Honoka and Kitayama Shizuku when she arrives at Class 1-A. As they start to chat, Morisaki Shun arrives with his friends, telling then that he was selected for the Public Morals Committee and start bad mouthing Shiba Tatsuya, going as far as to call him a Weed. This angers Miyuki who uses her magic to intimate the entire class and making it very clear that using forbidden derogatory terms in front of a member of the Student Council will not be tolerated.
Club recruitment week is in full swing, and Watanabe Mari is discussing the chaos with Saegusa Mayumi in the student council room, though Mayumi is procrastinating, much to Mari’s annoyance. Mari and the council discuss how it’s a free for all at the moment due to everyone being allowed to carry CADs because the school is keen to get as many people in clubs as possible. Mari mentions she will likely be running Tatsuya into the ground, and Miyuki assures her he will be useful. Mayumi mentions that the entrance exam scores got leaked so the top students will be targeted.
Meanwhile, Honoka and Shizuku are looking at clubs when they are recognised and subsequently mobbed by recruiters. Akechi Eimi appears on horseback and rescues the pair and takes them to the stables out back. There she formally introduced herself as Amelia Eimi Akechi Goldie of Class 1-B. A few moments after the pair return the introduction, the horse is spooked, and all three sense psion waves coming from the building nearby.
In the building, Shiba Tatsuya is arresting Kirihara Takeaki. Tatsuya’s apparent use of Cast Jamming without Antinite sparks interest in some of those observing. And a mysterious man orders someone to investigate Tatsuya.
Next day, Class 1-A are getting changed in the locker room and Eimi arrives to take to Honoka and Shizuku. She tells them about the incident with the kenjutsu team getting supressed by a single member of the Public Morals Committee with his bare hands. Miyuki confirms it was Tatsuya. Eimi showers Tatsuya with praise as the kenjutsu team is one of the top teams in the country.
As Honoka, Eimi and Shizuku try to leave they decide to use magic to sneak past the recruiters, since Honoka is an expert, though she needs some coaxing after the incident with Morisaki the other day. As they are sneaking past, they see Tatsuya dealing with two brawling students. An Air Bullet magic attack is suddenly fired at him from behind, but Tatsuya easily dodges it. Realising he is being deliberately targeted, Honoka, Shizuku and Eimi are shocked. This is when Eimi noticed Tatsuya is from Course 2.
Later, Tatsuya enters the student council room and is greeted by Miyuki who immediately knows Tatsuya has been attacked. Mayumi, Ichihara Suzune and Nakajou Azusa are baffled by Miyuki’s intuition. The siblings share a rather tender moment and Mayumi and Suzune are quick to tease the pair.
On the way home, Eimi Honoka and Shizuku discuss the attack. Eimi comments on Tatsuya being Course 2 and how impressive he is. Honoka and Shizuku are surprised by her refreshing attitude that the course divide is silly. Eimi concludes that the reason for the attack is likely jealousy. Honoka and Shizuku are reluctant to report it to the Student Council for fear of how Miyuki will react. Eimi, shocked to hear how terrifying Miyuki is, says then the solution is to form a detective club and catch the culprit first.
Late that night, the mysterious man discusses the attack on Tatsuya with a male student, and how the plan failed to get Tatsuya to use the cast jamming. The man suggests they use Mibu Sayaka and try to recruit Tatsuya.
The next day, Eimi, Honoka and Shizuku are watching Tatsuya from the roof hoping to get pictures of the Tatsuya’s assailant. They see Tatsuya get attacked and are surprised by his apparent use of Cast Jamming. Identifying the attacker, they try to intervene take pictures.
In the student council room, Miyuki receives a report on the incident in the gym form the Club Committee. Mayumi arrives and they discuss how it is making Miyuki uneasy as it appears someone is manipulating then kendo team and they wonder what is going on.
At home, Miyuki asks Tatsuya about the situation, and he brings up how Shizuku and Honoka along with Eimi have been watching him and taking pictures of the people targeting him. Tatsuya is concerned the three might dragged into something is this is all more than it seems.
At school, Eimi reveals the identity of the assailing student as Tsukasa Kinoe from Class 3-F, Captain of the Kendo Team and the three resolve to catch him.