The plan had been straightforward. Rear Admiral William T. Sampson ordered monitors, an armed tug, and a collier to proceed from Port Nipe, Cuba, to Cape San Juan on Puerto Rico's northeastern coast. They arrived on August 1, anchoring behind the cays of Icacos, Isla de Lobos, and Isla Palominos, out of sight from the mainland. Cape San Juan was supposed to be the landing site for Major General Nelson A. Miles and his invasion force. But sometime between July 21 and 24, Miles had unilaterally changed the invasion site to Guanica on the southwest coast -- and nobody told the Navy. Captain Frederick W. Rodgers of the USS Puritan found himself with warships, no army, and no orders. He sent reconnaissance parties ashore, and Lt. Commander James R. Selfridge seized the Cape San Juan lighthouse, posted the American flag, and told the lighthouse keepers to keep working as if nothing had changed.

When Dr. Santiago Veve Calzada, a prominent civic leader in Fajardo, realized the Spanish garrison had withdrawn and left the town defenseless, he begged San Juan to send troops. The situation was bewildering for Fajardo's residents: American warships sat offshore, Spanish soldiers had abandoned them, and rumors flew in every direction. Captain Barclay of the USS Amphitrite ordered a landing party of 28 sailors armed with rifles, pistols, and a 6mm Colt machine gun to reoccupy the lighthouse under Lt. Charles N. Atwater. Before any Spanish attack materialized, the Americans suffered their first casualty -- Naval Cadet William H. Boardman was mortally wounded when his revolver slipped from a faulty holster, struck the marble floor, and discharged into his thigh. He died two days later aboard the Amphitrite, one of only 23 combat-related Navy deaths in the entire Spanish-American War. Meanwhile, Barclay authorized about 60 women and children from Fajardo's prominent families to shelter inside the lighthouse with the sailors, while some 700 other residents camped in the surrounding hills.

On the evening of August 8, the sailors fortified the lighthouse. They blocked the windows, posted sentries, and mounted the Colt machine gun on the roof to sweep the approach lane. Local horsemen galloped up throughout the day with wild estimates of Spanish strength -- 500 men, then 800. Just before 11:00 that night, Lt. Atwater spotted figures in white at the edge of the woods, 250 yards out. At 11:45, moonlight broke through the clouds and revealed soldiers in the brush. Before he could pull his sentries inside, they came running with the alarm: Spanish troops were on the road. Gunfire erupted from the surrounding woods almost immediately. Atwater ordered the lighthouse lamp doused -- a prearranged signal to the ships offshore that the position was under attack. The cruiser USS Cincinnati trained her searchlight on the hilltop, and all three ships opened fire with their secondary batteries. At roughly 12:30 a.m., a six-pound naval shell crashed through the two-foot-thick parapet walls. It landed within arm's reach of six men. None were hurt -- the shell failed to explode.

Atwater immediately ordered the lamp relit. Spanish fire ceased around the same time, and the American sailors stopped shooting shortly after. They had fired 1,100 rounds from 22 rifles. Atwater estimated the Spanish force at about 72 infantry and 24 cavalry, with two killed and three wounded, including a lieutenant. The Americans suffered no casualties in the engagement. The next morning, Captain Barclay decided the lighthouse was not worth holding and withdrew everyone -- sailors and civilian refugees alike. First Lt. John A. Lejeune, who would later become the legendary Commandant of the Marine Corps, led the covering force from the USS Cincinnati. The women and children were transported to Ponce aboard the USS Leyden. After the Americans departed, Colonel Pino's men entered the town, tore down the two American flags flying over the Customs House and City Hall, and sent them to Madrid as trophies of war. Those flags remain in a Spanish army museum to this day.