Dr. Slump: Arale no Bikkuriman

ドクタースランプ　アラレのびっくりバーン

Arale and company arrive at a nice location for a picnic. They soon discover a beautiful stone with strange powers. Before they know it, a dangerous pirate and his mysterious ship invades their peace and steals the stone. Now it is up to them to retrieve the stone before it is used by evil hands.

(Source: BakaBT)