Maika Zenda is the main villainess of "Edible Plant Collecting Episodes" (currently not adapted into anime). She was a former elementary school teacher and a fiance of Touji Fukikoshi who is the victim of the case.
Maika's villainous reveal occurred shortly at the start of the episode, with the villainess bringing her fiance to the house that supposedly was given by her uncle as a present for their wedding. Instead, the evil Maika brought Touji to an estate he bought using the money he swindled from many women including her, and nonchalantly told him that she knew that he had been keeping a woman there. As Touji tried to explain himself, the villainess took a knife out of her purse and used it to stab her fiance to death as she told Touji to take those excuses with him the next world.
Later, Maika was introduced to Conan Edogawa and the Detective Boys by their teacher Sumiko Kobayashi and Rumi Wakasa as a fellow elementary school teacher at Gunma who shall aid them in collecting edible plant in the nearby mountain area, though Maika also added that she had resigned shortly prior to the event due to her marriage. The group got into Maika's car, which was laid with several folded cardboard box inside and which the villainess asked the Detective Boys to move it to the rear side. Shortly later, after Maika parked the car near a row of trees, the group arrived at their destination, took a photo, and began collecting the plants for their project (and as added by Genta Kojima, for their Tempura recipe). After sometimes, Genta became thristy from all the foraging, and the evil Maika suggested that she shall head to the car and bring back some drink for everyone, asking Ayumi Yoshida to help her with the job in the process. As Maika and Ayumi were about to head back to the group, the former claimed that she had lost one of her earings near the car and asked Ayumi to help her search for it. At this time, Conan and the rest smelled blood scent from nearby due to the wind had changed direction and discovered the lifeless body of Touji behind the car in the process, shocking everyone. The villainess then pretended to cry and rushed toward her former fiance, confusing everyone at the present.
After the police arrived to the crime scene, the evil Maika quickly became the prime suspect of the case as Inspector Misao Yamamura suspected that the villainess had staged the location and pretended to be the first discoverer along with the group and added that the motive behind the murder was because she no longer wanted to marry him, a fact that was not far from the truth. However, Sumiko, Rumi, and the rest defended Maika as they didn't see the corpse during the time they arrived, and the police can confirm their statement with the photos they had took. Sumiko then added that the murderer must had dragged the corpse to the current location when they left the car to go foraging, and that it was impossible for Maika to secretly move the car without starting it up first. During the investigation, the police discovered that Touji was infact a marriage fraudster under many names, with his true identity being Shigefumu Uruma, increasing Misao's suspicion on the villainess. Nevertheless, the suspicion eventually shifted to Uruma's lover, an unnamed woman who had been hiding inside the closet inside the estate with her hands splatted with the victim's blood. Additionally, the murder weapon was found in the trash bag inside the mansion, greatly incriminating her, much to the evil Maika's satisfaction.
Unfortunately for Maika, Conan successfully solved the trick that the villainess had used and tranquilized Misao in order to reveal the truth being the case. After Conan declared Maika as the the murderer, Conan revealed that Maika used the cardboard box to block the passengers' vision, leaving her as the only person who could see the corpse when they arrived. Afterward, she slowly parked the car to barely cover the corpse before they took a picture to complete part of her trick. Later, when the villainess returned to the car with Ayumi, she pretended to lose one of her earing and had Ayumi helped her search for it. While Ayumi was focusing on the ground, the evil Maika secretly moved the car by rotating one of the wheel forward, which was easily doable as the villainess didn't remove the car key when she parked the car.