Mama Wa Shougaku 4-Nensei

because her father was sent to london to work, natsumi, a 4th grade student, also must leave japan along with him. her classmates throw a farewell party for her. natsumi is prepared to go to london, but on the night before natsumi's arranged departure, a baby suddenly appears in her house after a roar of thunder! what's more is that this little baby is actually the one that natsumi will give birth to in fifteen years!