Your Kata (Ruby version) needs more extensive test coverage to prevent easy cheap-cheat solutions and/or logically flawed solutions. The most common way to increase test coverage is through the inclusion of randomly generated test cases at runtime so please add these. The lack of test coverage in a Kata as an Issue is recognised as an official CW stance.

Hello, welcome on CodeWars.

Why is secret_map an array of arrays , eg why . . .

[
  ["spain"], [], [], [], [], [],    [], [], [], [], [], [],   [], [], ["pirate"], ["pirate"], [], [],
  [], [], [], [], ["pirate"], [],   [], [], [], [], [], [],   [], [], [], ["pile_of_gold"], [], [],
]

. . . instead of . . .

[  "spain",,,,,,   ,,,,,,   ,,"pirate","pirate",,,   ,,,,"pirate",,   ,,,,,,   ,,,"pile_of_gold",,, ]

?