In The Mysterious Neighbor: The "Final year 3" Junior Detective Club Roundup, Ben a high school senior with a knack for detective work, finds himself entangled in a new mystery. The enigmatic neighbors, who have always been shrouded in secrecy, are at the center of his latest case. Ben's curiosity is piqued as he uncovers clues and unravels a web of intrigue that threatens to expose a shocking truth. With his sharp with and determination, Ben must navigate dangerous situations and uncover the secrets that lie hidden within the seemingly ordinary neighborhood.