Ranma ½ (1989)

S1E127 Legend of the Lucky Panda!

During a trek through the wilderness, Genma accidentally plunges into a river and sustains a head injury. Upon regaining consciousness, he discovers he has traveled back in time to a quaint village filled with people he recognizes from his past. As he navigates this unexpected journey, he encounters both challenges and opportunities that connect him to his former life in surprising ways.