Secret Seven Triple: "Secret Seven on the Trail", "Go Ahead, Secret Seven", "Good Work, Secret Seven"

Name: Secret Seven Triple: "Secret Seven on the Trail", "Go Ahead, Secret Seven", "Good Work, Secret Seven"
Author: /author/%E4%BC%8A%E5%A6%AE%C2%B7%E5%B8%83%E4%BE%86%E6%95%A6_(Five_on_a_Treasure_Island)