“The ocean is black, not blue. It is very dangerous, sister. Never let anyone you know cross that ocean the way that I did.”

Pablo Morales wrote those words to his sister after he miraculously managed to make it from Cuba to the United States in 1992. Like many other poor, desperate souls tired of scratching out a wretched existence under Fidel Castro, Pablo set off in a makeshift boat. Unlike most of the others, though, Pablo arrived in Florida.

We learn about his journey in “Shoot Down,” a riveting new documentary. We also learn how few actually make it. Roughly three out of four perish at sea. Between 1990 and 1996, more than 24,000 people died trying to make the 90-mile trek. They had done everything possible to reach freedom’s shore -- lashing inner tubes together, laying old doors on top of barrels. Paddling away with little more than the clothes on their backs.

To this day, Cubans are still trying to escape. Indeed, as I reported in a column last July, I actually met some Cubans as they arrived. I was forever changed by my interactions with these men, women and children as they experienced their first taste of freedom.

Pablo Morales was helped in his flight by the humanitarian aid group Brothers to the Rescue, founded only a year earlier to help Cuban refugees. He was so grateful for their assistance, and believed so deeply in their mission, that he joined the group to help other refugees complete the perilous journey. “On American soil, I experienced the immensity of liberty for which I longed in the land I left behind,” he said. “Here I will struggle tirelessly to see my country free of evil. I will strive to gain true freedom.”

Sadly, Pablo’s days as a rescuer were short-lived. The documentary is called “Shoot Down” for a reason: He and three other men -- Armando Alejandre Jr., Carlos Costa and Mario de la Peña -- were killed by Cuban fighter pilots on Feb. 24, 1994, as they flew over the Florida Straits, gunned down at the behest of a notorious communist dictator who spent nearly 50 years running his country into the ground.

To understand how such a tragedy could occur, it’s important to examine the history of U.S.-Cuban relations at the time. Prior to 1994, anyone who fled Cuba and reached our territorial waters was viewed as a political refugee and generally given asylum.

So Castro began using immigration as a weapon -- loading criminals and the mentally ill onto boats and shipping them to the United States. Florida officials cried foul, and the Clinton administration adopted the “wet foot, dry foot" policy, granting asylum only to Cubans who actually set foot on our shore, rather than to all who made it to open or U.S. waters. Worse, the Coast Guard was charged with preventing the freedom-seekers from reaching dry land.

As a result, Brothers to the Rescue re-tooled its mission. Instead of simply helping the people clinging to rickety rafts, they began encouraging the people of Cuba to press their government -- peacefully, non-violently -- to stop its repressive ways. They flew close to Cuba (and even over Havana) and dropped leaflets urging change. Angered, the Cuban government warned them to stop, but they persisted. “Shoot Down” gives you all the details, but suffice it to say, the pressure was building toward a showdown that February day.

Ask yourself, though: What moved Pablo Morales and his fellow rescuers to risk death? And why have so many people braved a treacherous sea to escape Cuba? Two words: compassion and freedom. Pity for the plight of other human beings moved Pablo, Armando, Carlos and Mario to put their lives on the line. And a burning desire for liberty has motivated thousands of Cuban refugees to do the same.

Life under the Castro regime has been so intolerable that the probability of perishing at sea actually paled in comparison. “Shoot Down” gives us several unforgettable images -- ones you won’t see anywhere else. You’ll shake your head in amazement when you see a picture of a billboard in Havana -- one depicting the Cuban flag with the words “Vamos bien” written on it. Translation: “We’re doing fine.”

If only they were. Thanks to the selfless humanity of people like Pablo Morales, though, thousands of Cuban-Americans now living in the United States are, in fact, doing fine. Let’s pray for those left behind and do what we can to ensure that, someday soon, an era of freedom will dawn for them as well.