Finally got it! Thank you! Btw, there's a few mispelling and wrong phrases on the portuguese dialogs... If you need help fixing those texts, let me know. (I'm brazilian)This mission is unlocked by talking to Emma when she is lying on the couch in the house, then you go with her and Lucy to a submarine ride, and Luci takes you to talk to her mom the mayor.
So you've just been helping Abigail on the farm and earning a little money, but the mission is not yet unlocked.