Agatha is a weird little girl who always invents some weird surveillance equipment and claims to be a detective.After moving into the new community with her mom, she received a case of investigating store theft.Soon Ah Gatha locked in the suspect: Vincent who lives next door.She sneaked into Vincent's house to investigate, but was discovered by Vincent.Mom asked Vincent to teach her roller skating on the excuse of just moving into the block to promote communication.Vincent disappeared for a while every afternoon. After following and inquiring, Agatha learned that Vincent once had a good friend, who believed that Vincent kidnapped the little girl in an abandoned factory.Agatha wanted to persuade Vincent, but Vincent, who was deeply misunderstood, ran away from home under the accusation of everyone.Mom thought Agatha was lying and shut down her detective center.Agatha, who is still addicted to the detective identity, saw Vincent sneaking home and quietly followed him, and found that he entered the store and stole some dog food.Vincent ran away angrily, and Agatha, who was holding dog food in her hand, was mistaken for a store thief.Agatha understood everything. It turned out that the good friend "little girl" was just Vincent's dog. His brother was allergic to animals and had to give the dog away. However, Vincent couldn't bear it and took it back and put it in the factory. It was a last resort to steal the dog food.The sick dog bit Vincent, and Agatha came to the factory and saw Vincent with fever. She hurriedly called for rescue and rescued Vincent and the dog.Vincent finally got better and gave the puppy to Agatha, who likes dogs, and the reputation of Agatha's little detective also spread.