The Water Seven arc in One Piece begins when the Straw Hat Pirates arrive at the vibrant city of Water Seven, known for its advanced shipbuilding and canals. They seek to repair their beloved ship, the Going Merry, but soon discover it is beyond saving.

As they explore the city, they encounter the Franky Family, a group of shipwrights and cyborgs. After a series of misunderstandings, tensions rise when the Franky Family steals the Going Merry, leading to conflict with the enigmatic government organization, CP9.