Dark Life

In the story dark life the main character Ty, is an unusual teen.  He's 15 and lives with his family beneath the sea.  His family owns 200 acres of land on the sea floor.  Ty loves exploration, especially exploring coldsleep canyon.  To go there alone is completely forbidden.  but he regards and does it anyway.  however while going down in to the deep dark abyss he remembers why hes going down there in the first place.  His brother, he died in a submarine crash and Ty wants to investigate.  So he goes, not to deep though because of the pressure.  And he spots an object but when gettin closer he sees a mini submarine.  He then pushes the opening panal and it sucks him in.  There is air not much but some air.  Ty starts to hear banging on the door so he looks though the glass.  A ton of sharks swarm the sub.  A door opens Ty had gun ready and out emerged a girl.  Her name was Gemma.  

She had rented the submarine from the trade station by the docks.  She did not know how to drive it well so she crashed it.  luckily Ty came and found her or she could have died in that Submarine.