Mystery is related to Secret. Secret is related to Agent. Agent is related to Sugar. 
Girlfriend is a type of Lover. Lover is a synonym of Fan. Fan is related to Blow. 
Mystery <--RelatedTo--> Secret <--RelatedTo--> Agent <--RelatedTo--> Sugar 
Girlfriend --IsA--> Lover <--Synonym--> Fan <--RelatedTo--> Blow 