On Saturday, Nguyen and dozens of other students participated in Coastal Cleanup Day, picking up trash along the north bank of Mosher Slough, when he stumbled on a piece of another family's history.
"So it was like under a bridge of a homeless encampment, that was with a bunch of stolen mail," Nguyen explained to the couple.
He went through the mail, he found a passport, pictures and some toys.
"And I saw the piece coming out, and I saw this, and I read the letter," he said. "And I knew it was something important 'cause it was from 1941."
The letter was written Dec. 15, 1941, eight days after the Japanese bombed Pearl Harbor.
Greg's father, George, was in the military -- stationed in Virginia and homesick, and was writing to Greg's mom.
Greg read out loud a portion of his dad's words.
"I received your telegram yesterday, asking me if I was coming home for Christmas. Well, I won't be able to go home from here because we are going to ship out before this week is over."
George was later shipped off to Europe.
"I'd never ever thought I'd get it back again. It was amazing when I first got possession of it. Just seeing his letter and now that I have it back, we won't put it in anymore storage units," Greg said.
"I'm feeling great that it's returned to the right owner. I knew it means something to someone, so I kept it," Nguyen said.
Chemistry teacher Steve Meredith says this was a Coastal Cleanup Day that holds a far greater meaning to his students.
"Whenever you get personal items that kinda connects Coastal Cleanup Day to something personal in people's lives, I think it becomes far more meaningful," Meredith said.
And an even deeper meaning for the Almeidas.
"Hope. Hope for the future. We have kids like this in our future, it's a good thing," added Greg's wife, Rosemary, with grateful tears.
Related: Also see these iconic WWII photos:
Iconic WWII Photos Joe Rosenthal
Iconic WWII Photos Joe Rosenthal
U.S. Marines of the 28th Regiment, 5th Division, raise the American flag atop Mt. Suribachi, Iwo Jima, on Feb. 23, 1945. Strategically located only 660 miles from Tokyo, the Pacific island became the site of one of the bloodiest, most famous battles of World War II against Japan. (AP Photo/Joe Rosenthal)
U.S. Marines of the 28th Regiment, fifth division, cheer and hold up their rifles after raising the American flag atop Mount Suribachi on Iwo Jima, a volcanic Japanese island, on Feb. 23, 1945 during World War II. (AP Photo/Joe Rosenthal)
Australian and New Zealand fliers arrive at San Francisco on Matson Liner Mariposa Nov. 4, 1941. (AP Photo/Joe Rosenthal)
Japanese arms plant precision machinists at work on the breach end of a gun barrel in Tokyo, Dec. 1, 1941. Armament production is proceeding at a high pitch of intensity and efficiency. (AP Photo/Joe Rosenthal)
Japanese guns and material captured at Kokumbuna in the Solomon islands are brought from the front in a jeep on Feb. 12, 1943. American soldiers look them over. Much booty was captured by the Americans when they took Kokumbuna, Japanese strong point on Guadalcanal last January. (AP Photo/Joe Rosenthal)
U.S. Marine paratroopers, in training at a South Pacific base, use a portable tripod to shake out their parachutes and remove dirt and leaves on April 13, 1943. S/Sgt. Robert E. Sale of Chicago, right, directs the operation. The towers in the background are portable cabinets for drying wet chutes with heated air. (AP Photo/Pool/Joe Rosenthal)
Marine gunner Charles E. James of Hartland, Wis., demonstrates various methods of snap-shooting pistols to a group of U.S. Marines in training at a Pacific base on April 13, 1943. (AP Photo/Joe Rosenthal)
Cyclops airdrome in the Hollandia area of Dutch New Guinea on May 12, 1944 is full of activity as Army transport planes land and takeoff from this field captured from the Japanese. In the foreground is the wreckage of a Japanese zero. Soldiers are unidentified. (AP Photo/Joe Rosenthal/Pool)
Sitting on the remains of a destroyed Japanese Zero at Hollandia, New Guinea on May 14, 1944, are these American soldiers who helped occupy the Japanese-held air field. Left to right: Pvt. Angelo Gemelli, Chicago, Ill.; Pfc. Troy A. Martin, Missoula, Mont.; Sgt. Henry H. Coldeway, Hermleigh, Texas; Pfc. David C. Calvert, Great Falls, Mont.; Pvt. John Henry Pavlowski, Syracuse, N.Y.; T/Sgt. Howard Sandberg, Ronan, Mont.; and T/Sgt. Stanley P. Mach, Posen, Illinois. (AP Photo/Joe Rosenthal)
Sgt. Raymond W. Davis (lower center), of Utica, Ohio, shows a group of home state boys the proper method of servicing a motor, somewhere in the South Pacific on June 9, 1944. Standing around the sergeant, left to right: Pvt. Guadelupe Barron, Dayton, Ohio; Cpl. Otis C. French, Dayton, Ohio; Cpl. Willis L. Felver, Piqua, Ohio, and Pfc. Frank E. Davis, Massilon, Ohio. (AP Photo/Joe Rosenthal)
Five New Jersey boys strike this pose somewhere in the South Pacific on June 9, 1944. Left to right: Warrant Officer Frank P. Bingert, New Brukswick; S/Sgt. John Petrjcik Jr., Meyuchen; T/3 John Nagy, Perth Amboy; T/5 Mickey Procadding, Princeton; and T/5 Philip Roman, Passaic. (AP Photo/Joe Rosenthal)
American artillery fire, which hit the tree under which they were sitting, killed these three Japanese as American forces established a beachhead on Saipan in the Marianas, June 26, 1944. The invasion, closest yet to Japan, was launched on June 14. U.S. Marines are in background. (AP Photo/Joe Rosenthal)
These Wisconsin lads find a stack of heavy duty tires the ideal spot on which to relax from their chores at a base in the South Pacific on June 9, 1944. Left to right: T/5 Daniel Buress, of Kenoshan; Sgt. Floyd Davison, of Milwaukee; Cpl. Adolph D. Larson, Deerfield, and Cpl. George Mazanek, Green Bay. (AP Photo/Joe Rosenthal)
Marines take advantage of natural cover at the beachhead near Asan, Mariana Islands, Guam, July 1944. In background is a burning "duck". (AP Photo/Joe Rosenthal)
U.S. Marines move forward in the rain, toward junction with 1st Marine Brigade at the front lines, July 1944. (AP Photo/Joe Rosenthal)
Soldiers of a parachute unit wash their bodies and clothes, New Guinea, Jul. 11, 1944. (AP Photo)
Transporting a piano to a paratroopers base in New Guinea is no easy feat but these men accomplished it, shown July 12, 1944. Left to right: Pvt. Mike Pazinko, Olyphant, Pa; Pfc. Salvador R. Fiorelli, Philadelphia, Pa; 1st Lt. Arthur E. Schuder, Atlanta, Ga. (AP Photo/Joe Rosenthal)
Marines land on coral reefs during U.S./Japanese warfare, Guam, Mariana Islands, Jul. 21, 1944. (AP Photo/Joe Rosenthal)
Vehicles are slung over the side of a transport ship in preparation to being run to the Guam shore in a landing craft, July 21, 1944. In the background, partially obscured by haze and smoke from shelling is another landing craft. Photo made on the first morning of invasion to retake Guam. (AP Photo/Joe Rosenthal)
Guam in the Mariana Islands is pictured on Jul. 27, 1944, during U.S./Japanese warfare. (AP photo/Joe Rosenthal)
Wounded soldiers are carried on stretchers towards a beach where they will be evacuated to a hospital ship, Guam, Mariana Islands, Jul. 27, 1944. (AP Photo/Joe Rosenthal)
Among equipment abandoned by the Japanese as Marines stormed forward is this 25-millimeter anti-aircraft gun near Piti, past Tepungan, July 27, 1944. (AP Photo/Joe Rosenthal)
A view of destruction in outer Agana, Mariana Islands, Guam, Aug. 1944. (Joe Rosenthal)
Marine Corps General A. H. Noble, left, looks on as Major Gen. A. H. Turnage frisks a captured Japanese carrier pigeon on Guam island in the Marianas, Aug. 2, 1944. Pfc. Louis E. Cook, Jr., of DuQuoin, Illinois, keeps a close watch on the proceedings. (AP Photo/Joe Rosenthal)
Wreck of a Japanese plane on Tiyan airport after seizure by Marines on the Guam, Aug. 2, 1944. (AP Photo/Joe Rosenthal)
U.S. troops stop to eat on the road to Agana, the capital of Guam, Aug. 10, 1944. (AP Photo/Joe Rosenthal)
U.S. Marines pose at the graves of dead comrades in Guam, Aug. 10, 1944. (AP Photo/Joe Rosenthal)
Tiny natives of Guam hold home-made American flags made by their mothers from parts of dresses while in custody of the Japanese, Aug. 10, 1944. The children waved the flags when the Yanks moved in. (AP Photo/Joe Rosenthal)
Supported by tanks, Marines of the 1st U.S. Division inch their way up on the beach of Peleliu, during the invasion of the island in the Palau group, on September 14, 1944. (AP Photo/Joe Rosenthal)
As the U.S. invasion of Peleliu gets underway, various types of landing craft approach the island in the Palau group, ferrying men and material to the beaches, on September 14, 1944. (AP Photo/Joe Rosenthal)
U.S. troops of the First Marine Division storm ashore from beached "Alligator" vehicles at Peleliu Island, Palau on Sept. 20, 1944 during World War II. The invasion started Sept. 14. The smoke is from a burning "Alligator." (AP Photo/Joe Rosenthal)
Soldiers stand by a crashed Japenese bomber on Peleliu, Republic of Palau, Sep. 22, 1944. (AP Photo/Joe Rosenthal)
U.S. Fourth Division Marines move in from the beach on Iwo Jima, Japanese Volcanic Island, on Feb. 19, 1945. A dead Marine lies at right in the foreground. Mt. Suribachi, in the background, was turned into a beehive of guns by Japanese troops. It was scaled by the U.S. Marines, who took control. (AP Photo/Joe Rosenthal)
U.S. Marines aboard a landing craft head for the beaches of Iwo Jima Island, Japan, on Feb. 19, 1945 during World War II. In the background is Mount Suribachi, the extinct volcano captured by the Marines after a frontal assault. (AP Photo/Joe Rosenthal)
A U.S. Marine, center, is shot dead during battle for Iwo Jima, Japanese Volcano Island stronghold, on Feb. 19, 1945 in World War II. (AP Photo/Joe Rosenthal)
U.S. Marines of the Fourth Division shield themselves in abandoned Japanese trench and bomb craters formed during U.S. invasion and amphibious landing at Iwo Jima, Japanese Volcano Island stronghold, on Feb. 19, 1945 in World War II. A battered Japanese ship is at right in the background at right. (AP Photo/Joe Rosenthal)
Two U.S. Marines, slumped in death, lie where they fell on Iwo Jima, among the first victims of Japanese gunfire as the American conquest of the strategic Japanese Volcano Island begins on Feb. 19, 1945 during World War II. (AP Photo/Joe Rosenthal)
U.S. Marines offer a Japanese prisoner of war, whose face is obliterated by censors, a cigarette after he is captured during American invasion of Iwo Jima, Japanese Volcano Island stronghold, on Feb. 28, 1945 in World War II. (AP Photo/Joe Rosenthal)
U.S. Marines kneel in prayer before they receive communion during a lull in the fighting for Motoyam Airstrip No. 1 on Iwo Jima, March 1, 1945. From left to right: Pfc. Edmond L. Fadel, Niagara Falls, N.Y.; Pvt. Walter M. Sokowski, Syracuse, N.Y.; and Pvt. Nicholas A. Zingaro, Syracuse, N.Y. (AP Photo/Joe Rosenthal)
Joe Rosenthal, of the Associated Press, photographer with the wartime still picture pool, looks over the scene at Iwo Jima, Japan on March 7, 1945, from which he has sent some of the most graphic pictures of the Pacific war. (AP Photo/U.S. Marine Corps)