Marine behavioral biologist Nate Quinn and his crew explore the question-Why do humpback whales sing? Until the extraordinary day when a whale lifts its tail into the air to display a cryptic message spelled out in foot-high letters. Trouble is, Nate's beginning to wonder if he hasn't spent just a little too much time in the sun. Because no one else on his team saw a thing. But later, when a roll of film returns from the lab missing the crucial tail shot-and his research facility is trashed- Nate realizes something very fishy indeed is going on.