"Little Chao Lost" (夏休み・チャオ〜な観察日記,Natsuyasumi chao 〜na kansatsu nikki?, lit. "Summer Vacation Chao Observation Diary") is the twenty-second episode of the anime series, Sonic X. It first aired on 31 August 2003 and 28 February 2004 in Japan and United States respectively.
The episode starts with Mr. Tanaka praying to a statue. Tails, Amy, Cream, Cheese, Chris, Frances, Danny and Mr. Stewart are all waiting for a bus which would transport them to a beautiful valley which is notable for being Mr. Tanaka's homeland as a youth where Mr. Tanaka is waiting for them to set up camp there. Sonic also tags along but instead of participating in the camp with everyone else, he visits the cityside for sightseeing.
The camping gang quickly settled in to the campsite and participated activities such as cooking and catching insects. However, Cheese, while swimming, is accidentally swept by the rapid current into the main stream leading to Cream bursting with tears. Amy and Tails reassured that Cheese is a very good swimmer and so everyone (except for Mr. Tanaka and Amy) searched across the surrounding valley for Cheese's whereabouts. Meanwhile, Dr. Eggman, with Decoe and Bocoe, are also hiking through the valley. Eggman gets frustrated with his two robot henchmen complaining throughout the hike. Eggman however notices the search gang are nearby and the trio of villains suspect that they are looking for a Chaos Emerald but Eggman gets bitten by a mosquito, followed by a vicious moth.
The search party comes to a stop before a small tunnel, wondering if Cheese could be at the end of the stream after the tunnel. As Mr. Stewart is physically too big to fit in, the children (including Tails and Cream) went through it. At the end of the path, the children have discovered a Chao colony inhabited by many Chao, much to Tails and Cream's surprise. Cream rejoices when she finally found Cheese. The children decide to spend some time playing with the other Chao before heading back to the campsite. Meanwhile as the doctor and his two robot henchmen continued to hike through the valley and Decoe and Bocoe complained again, Eggman got fed up and ordered Decoe to unpack his knapsack which revealed to be the Selection Machine. Using the machine, Eggman then summons his new E-66 Da-Dai-Oh from his Egg Fort II.
Back at the campsite, Amy wonders the whereabouts of the search party while Mr. Tanaka responded open-heartedly that they are just fine. At that moment, a worried Mr. Stewart returns to the campsite showing concern for the whereabouts of the children and then Mr. Tanaka, Amy and Mr. Stewart left the campsite to look for the children. Suddenly, Da-Dai-Oh flies past over the campsite indicating that Eggman is causing trouble again. Unfortunately, Eggman, Decoe and Bocoe ambushes the children riding on the Da-Dai-Oh demanding for a Chaos Emeralds. Chris yelled back that there are no Chaos Emeralds around the valley and despite this, Eggman ordered Da-Dai-Oh to attack. After taking one step, Da-Dai-Oh suddenly skids (due to walking on slippery mud) and crashes into the lake below. The impact of the crash pollutes the water as witnessed by Cream so the children quickly rushed to the Chao colony.
After the efforts of Decoe and Bocoe cleaning Da-Dai-Oh and displacing it somewhere else, the trio of villains spot Sonic carrying a bag of souvenirs who is surprised to meet them. Sonic questions Eggman's presence in the valley and the trio replied that they are just here for a vacation. Eggman orders Da-Dai-Oh to attack Sonic but the blue hedgehog evades the attack with ease and destroys the robot, sending the trio of villains flying through the sky to the horizon. Amy, Mr. Tanaka and Mr. Stewart just arrived into the scenery informing Sonic that he needs to find the others.
Sonic eventually found the children attempting to filter the mud out of the polluted lake in the Chao colony. He then filters the mud out of the polluted water using his speed. Later that night, the cast sit and laugh around the campfire as Mr. Tanaka mentioned he stumbled upon a Chao colony when he was a youth while the episode draws to a close.
The following scenes have been cut from the English dub:
At the beginning of the episode, Mr. Tanaka is seen praying to the statue. The Japanese version extends this by viewing him from a different angle (cut).
After both of the respective English and Japanese opening titles roll, the bus moves steadily towards the camera's direction (cut) before the camera snaps to the inside of the bus.
While Sonic is sightseeing he runs past a house. He then comes back to it only to have a brief conversation with two Japanese women wearing different colored kimonos (cut) before the viewers see the campsite.
This scene (cut) appears before Sonic sees a chef deep-frying some treats.
After a Chao is seen pulling Tails' whiskers, Cream rushes to the edge of the lake (cut) before calling out to Cheese.
After Chris attempts to say what the Chao are saying, this scene (cut) is then shown. Note that this scene appeared in one of the later episodes including the English version.
As the E-66 flies overhead past the campsite, Mr. Tanaka gives a shock facial expression (cut).
At the end of the episode, there is a slightly close-up scene of the campfire (cut).