They're hunting these whale looking things and when they kill them, they drill a hole up into their adrenal gland and fill up this giant vial with that they call liquid gold, which has anti-aging properties and "way way way more than you can get from a human being." (So....they usually get it from human beings?)
It's so valuable they don't even bother with the rest of the whale's body. They just take the adrenochrome and bounce.
I hated the movie. And yes! I totally got that too...