You have to collect the 4 objects that are scattered on the seabed and, when you have them all, take them back to the boat. This is the objective. For this, you must be careful not to lose all your oxygen. The way to lose it is by touching plants or bugs that swarm by the sea ... well, and just being underwater makes you lose it little by little. To retrieve it: rise to the surface or collect bubbles that you will find hidden there ... each bubble gives you a life, that is, 100 more units of oxygen. Parts with only 100 units, and as you lose oxygen you get a lot ... so look for oxygen!