At dawn, Mara stood above the harbor when she noticed something strange: long lines of waves were crossing each other, creating perfect squares across the sea. Two swells were approaching from opposite directions, and when a fishing boat entered the pattern, it suddenly began rising and dropping at dangerous angles. Then Mara saw a dark shape moving beneath the boat. As the vessel tilted sharply, she ran to the harbor office and warned an old coast guard named Elias.

Elias immediately understood the danger. “Cross sea,” he muttered, explaining that opposing currents could trap a boat between waves. He called the harbor patrol and ordered nearby vessels to return. But the dangerous pattern was already moving toward the harbor entrance faster than expected. Soon, the patrol boat was struggling against waves coming from both sides. A massive swell rose like a wall, forcing the crew to turn directly into it to avoid capsizing.

Mara helped close the beach gate and warned people to stay away from the water as the square waves spread along the coast. Elias explained that distant storms and local currents were pushing against each other, creating the dangerous crossing sea.

Then the radio crackled with worse news: another boat had been spotted offshore, drifting without power. Elias prepared to launch the rescue skiff, but stopped Mara from joining him. “You stay here and watch the harbor lights. If they disappear, call me immediately.” Mara nodded and watched the darkening sea, knowing the peaceful surface had hidden a serious danger.