Mysterious is a synonym of Secret. Secret is a synonym of Hidden. Hidden is related to Base. Base is related to Place. 
one thing you do when you Fish is Catch. Catch is a synonym of Capture. 
Mysterious <--Synonym--> Secret <--Synonym--> Hidden <--RelatedTo--> Base <--RelatedTo--> Place 
Fish --HasSubevent--> Catch <--Synonym--> Capture 