Mamoru Hosoda	...	(Director)
Satoko Okudera	...	(Writer)
Sumiko Fuji	...	Sakae Jinnouchi
Ryûnosuke Kamiki	...	Kenji Koiso (voice)
Ayumu Saitô	...	Wabisuke Jinnouchi
Nanami Sakuraba	...	Natsuki Shinohara
Mitsuki Tanimura	...	Kazuma Ikezawa
Patrick Mölleken	...	Takashi Sakuma (voice: German Version)
Yôji Tanaka	...	Yorihiko (voice)
Takahiro Yokokawa	...	Takashi Sakuma
Michael Sinterniklaas	...	Kenji Koiso
Brina Palencia	...	Natsuki Shinohara
Pam Dougherty	...	Sakae Jinnouchi
Todd Haberkorn	...	Takashi Sakuma
J. Michael Tatum	...	Wabisuke Jinnouchi
Maxey Whitehead	...	Kazuma Ikezawa
John Swasey	...	Mansuke Jinnouchi
Shelley Calene-Black	...	Mariko Jinnouchi
Lydia Mackay	...	Naomi Miwa
Mike McFarland	...	Shota Jinnouchi
Monica Rial	...	Yumi Jinnouchi
Barry Yandell	...	Mansaku Jinnouchi
Chuck Huber	...	Riichi Jinnouchi
Cynthia Cranz	...	Rika Jinnouchi
John Burgmeier	...	Tasuke Jinnouchi

Summary: Kenji Koiso, an eleventh grade math genius, agrees to take a summer job at the Nagano hometown of his crush, Natuski. When he arrives, he finds that her family have reunited to celebrate the 90th birthday of the family matriarch. His job is to pretend to be Natsuki's fiancé. Meanwhile, his attempt to solve a mathematical equation causes a parallel world's collision with earth.