"Schools Fiction." . . "Children's stories." . . "Technology Fiction." . . . . "Friendship Juvenile fiction." . . "Ninjas Fiction." . . "Friendship Fiction." . . "Competition (Psychology) Fiction." . . "Schools Juvenile fiction." . . . . . . . . . . . . . . . "Electronic books"@en . . "\"Best friends and ninjas-in-training Joey and Johnny are sent on a special mission to investigate their rival ninja school's use of advanced technological weapons\"--"@en . "Get mooned"@en . . "\"Best friends and ninjas-in-training Joey and Johnny are sent on a special mission to investigate their rival ninja school's use of advanced technological weapons\"--" . "Get mooned" . . . . . . "Humorous stories"@en . "Humorous stories" . . "Ninja Juvenile fiction." . . "Competition (Psychology) Juvenile fiction." . . "JUVENILE FICTION / Comics & Graphic Novels / General." . . "Best friends Juvenile fiction." . . "Humorous stories." . . "Technology Juvenile fiction." . . "Best friends Fiction." . .