Cliff Valley School had always seemed too cramped, too predictable to Victor. Together with two friends - Maja, known for her sharp tongue and flair for technology, and Tobias, an incorrigible dreamer - they decided to use the last days of the summer holidays for something really unusual. The lighthouse at the end of the rocky promontory was a place where no one had looked in years. Legends circulated that its light once brought back those who died at sea. Some said it was just a fairy tale for tourists, others that the lighthouse keeper who lived here had disappeared under mysterious circumstances. That afternoon, the sea was calm, though an uneasiness permeated the air. The friends crept through the overgrown path, unconcerned about the warnings of the rusty plaques. Maja took the torch out of her phone, Tobias jotted down everything in his notebook, and Viktor Victor was attracted to the tattered metal door handle, as if something was waiting for them inside. Inside, there was semi-darkness and the smell of old paper. On one of the desks lay a leather-bound diary. The pages were written in a fine, slanted script, full of ciphers and symbols. "It looks like a code," spoke up Maja, fascinated. "Or a warning," added Tobias, looking at the drawings depicting the mysterious lantern mechanism. Suddenly, a sound came from outside - a quiet but firm clatter, as if someone or something was moving around the building. Victor went to the window, but in the thickening gloom all he could see was a shadow, gliding towards the lighthouse. "We shouldn't be here," whispered Maja, but at the same time she couldn't take her eyes off the page of the journal describing the "Last Lighthouse Keepers Code". Tobias, bemused, was already solving the first puzzle. The door suddenly shook under a heavy impact. The friends froze, with the journal in their hands and unanswered questions, not yet knowing what awaited them beyond the threshold of the lighthouse....