Characters introduced
 Part 1
It's summer vacation and the Detective Boys (along with Agasa) are gathered on the school ground for morning radio exercises. Professor Agasa had told the Detective Boys about these exercise once when they went to see the fireworks. When Mitsuhiko doesn't show up for the exercise, Conan, Genta, Ayumi, Haibara and Agasa decide to visit Mitsuhiko, believing that he was ill. Mitsuhiko's older sister, Asami Tsuburaya, tells them that he left saying that there was a "camping trip" with the Detective Boys, so Mitsuhiko prepaired his schoolbag to go with them and took some candies wrapped in bamboo leaves. Concerned, the kids and Agasa set off a journey into the forest in search of their best friend.
| Missing Person
|| Gunma Forest
|| Mitsuhiko Tsuburaya
| When Mitsuhiko suddenly disappeared, it's up to the Detective Boys to find out where he is!
Asami told the Detective Boys that Mitsuhiko had borrowed from her a sunscreen that she had bought, which came from abroad. She also mentioned that her brother often saw a girl which worked at a flower shop, and probably was in love with her. The girl said she hadn't seen Mitsuhiko that morning, but then she realized she had seen him indeed about to take a bus. She called his name, but he didn't reply. The guys also heard from her that Mitsuhiko had been wearing his cap, smelled like lemons, and that she had seen him being warned by two men after mentioning the name of some samurais. She started wondering which they were, and she mentioned Uesugi, Takeda, Toyotomi and Takegawa.
With no more clues, the Detective Boys asked the bus driver about Mitsuhiko. He told them that he was in his bus and that he remembered him because he wasn't looking through the window but ahead, as if he was worried. He had got off the bus at a train station, so his friends went to look for him there. One of the employees there remembered him because he had bought an adult ticket by mistake and asked him to change it in a hurry. The ticket was 1,900 yen so it could be a ticket to Chiba or Gunma. A worker at Nakanojō Station in Gunma said he had seen Mitsuhiko hiding there for a while and then leaving. The Professor and the Detective Boys start looking for Mistuhiko in the Gunma Prefecture with Conan's tracking glasses... Where could he be?
 Part 2
In the forest, the Detective Boys and Agasa run into Officer Yamamura. He tells them that they have let loose a very dangerous criminal killer known as Ki'ichiro Numabuchi by accident, and that they were in search for him. Having met with this serial killer once before in Osaka, Conan knew how dangerous Numabuchi was already. He was there with the Gunma police because he testified that his fourth victim was buried there, as his mother was born in Gunma, but they haven't been able to find this corpse yet. Mistuhiko is in fact in the forest, but for some reason he can't pick the Detective Badge to talk to Conan. Everyone is afraid this serial killer could be targetting Mitsuhiko. After a long while of searching him, Conan starts deducing the truth.
The scent of lemon was nothing but just the sunscreen Mitsuhiko borrowed from Asami. It smelled like that because it also was an insect repelent. Suddenly, Ayumi spots Numabuchi up in a tree, but he flees. Haibara starts wondering why she can't feel people from the Black Organization anymore...
 Manga to anime changes
- The anime shows the train arriving to Gunma, following with the Detective Boys asking the train station employee there about Mitsuhiko. The manga just transitions to the group just having arrived at Gunma after hearing about that he might have gone there.
- After learning that Ki'ichiro Numabuchi is loose in the forest, Conan has a flashback in the anime to his previous encounter with Numabuchi.
- Episode 289's ending adds a scene with Numabuchi continuing to evade the police after Mitsuhiko discovers Conan and company are trying to contact him.
- Episode 289 features the first use of the show's seventh post-credits stinger image, featuring a new image of Conan looking at the audience, with Shinichi's face in the background.
- The bus and the driver are those from The Mysterious Passenger.
 BGM listing
 Part 1
 Part 2
 In other languanges
|| En Mitsuhiko es perd al bosc
|| Wo ist Mitsuhiko?
|| Where is Mitsuhiko?
|| Mitsuhiko sparisce nel bosco
|| Mitsuhiko Disappears in the Forest
|| Mitsuhiko perdido en el bosque
|| Mitsuhiko và khu rừng bí ẩn
|| Mitsuhiko and the Mystifying Forest
 See also