Ecchan arrives like a force of nature that the show never quite explains and doesn't need to. She's a ninja descendant who talks to animals, sleeps wherever she lands, and solves problems by being too competent and too weird for anyone to argue with. A 1971 magical girl show that doesn't care about origin stories or emotional stakes, just what happens when a girl who shouldn't exist decides your school is interesting enough to stay.

Ecchan arrives at Mitsuba Elementary School as a transfer student with no house to live in. She looks like an ordinary girl, but she is a superb athlete, can talk to animals, and says she is the 33rd descendant of the famous ninja Sarutobi Sasuke. Her dog Puku can talk too. She spends a night in Miko-chan's room and is once thrown out, but after she puts out a fire, the family thanks her by letting her stay with them. From there she begins to make a name for herself at school in this comedic magical girl series.