writing

Hi, can someone please help me check whether this sentence is grammatically correct?

Nobita and his gang's escapade through time, 70,000 years ago. Shortly as they arrive in what-is-supposedly Japan, they realize that they miss home, so they get on board on the ship to return to the 20th century, only to realize that a cave boy has broken and boarded the ship as well. As Nobita and the gang drop him home, they have to instead fight for the boy's trible, which has been attacked and abducted by a king of spirits and a rivaled tribe.