Chiyomaru is a Shiba Inu who meets Lassie on the busy road.
He is brown Shiba Inu and have dots on his forehead.
He was abandoned as a puppy but was found by the kind woman Masumi. It was raining hard and Masumi couldn’t get Chiyomaru to come out from his hiding place. A man, Seinosuke Ando, comes by and helps Masumi in which they fell in love and Chiyomaru became their pet dog. However, his mistress worked so hard that she got sick and died leaving Chiyomaru in deep sorrow. And his life became much worse when his master, Seinosuke found a new rich and spoilt lover by the name of Machiko whom Chiyomaru hated her and felt that his master didn’t honour the memory of Masumi. One day Machiko cleans the house and finds some an old shirt which had belonged to Masumi which she gives the shirt to her poodle Pamella. Chiyomaru got so angry that he started biting the poodle which as a result, Machiko beats Chiyomaru half to death and leaves him in the forest to die.
When Chiyomaru meets Lassie, he won’t follow his advice on going back to his master. He still misses Masumi and has started hating Seinosuke because of all the sudden changes in his life when the new lover was brought with him. In the end, Lassie lures Chiyomaru close to Seinosuke after seeing Lost-and-Found posters of Chiyomaru. When Chiyomaru sees his master pay respects at Masumi’s grave, he forgets all hatred and jumps to his old master's arms and is once more home. Before everything returns to normal, Chiyomaru busts Machiko in trying to steal Seinosuke’s fortune resulting in his master breaking up with her and returns to his peaceful life together with Chiyomaru.