Granpa Bill and his grandchildren Alice and Henry are getting ready to watch a sci-fi movie, but... where’s Henry?

Thinking he is in the toilet, Granpa Bill and Alice start watching the movie,  but everything will change when, among the radioactive mist, they see... Henry! Somehow, he got inside the movie, and now that he has been in touch with the radioactive mist, he starts getting smaller and smaller...

Will he survive to the dangers of a huge world and be able to get out in his normal size?