Nathan Rivera stood on the lifeguard tower, his eyes scanning the horizon where the deep blue of the Pacific met the cloudless California sky. Early risers were jogging along the shoreline, and a few families were setting up for a day of sun and sand. Nathan climbed up to his post, slipping on his sunglasses as he scanned the water. His shift had just begun, but he was already in his element.

Around midday, the beach was bustling. Families splashed in the shallows, surfers carved through the waves, and sunbathers lounged on towels, soaking in the warmth. Nathan remained vigilant, his eyes never straying far from the water. It was during this busy time that things could quickly take a turn, and he was always prepared.