The video features researches making an instructional film on how to catch and safely release a marlin. It is being shot from on board a boat as well as from a photographer bobbing in the water. Everything is going as planned until they get the marlin next to the boat and prepare to set it free. At the point, a monster mako shark appears out of nowhere and violently takes hold of the tethered marlin.
What makes this video so impressive is that the photographer in the water continues shooting the attack as a large pool of blood begins to fill the water. You gotta give a hand to Australian photographer Al McGlashan for showing some serious guts.