The Stone Invitation. The Mountain Academy: The Essence Cost Series, #1

In a world where every flicker of magic drains a wizard's very life force, twelve-year-old Elara Vance has always been clumsy and inexplicably exhausted. Her life changes forever when a seemingly impossible stone invitation arrives, revealing a hidden world where magic has a steep, physical cost. She is invited to attend the Mountain Academy of Arcane Studies, a secure fortress designed to teach the next generation how to manage their limited essence and obey the strict laws of balance.
Upon arrival at the imposing, stone-carved academy, Elara is sorted into the intellectual and efficient Ventus house. She quickly befriends the cautious Ben (Terrus) and the logical Serena (Ventus), and finds herself drawn to the brilliant, unnervingly composed Ancient Runes Professor Kaelen, a man who preaches a radical philosophy of "power without effort" and "efficiency above all else."As external political tensions rise and a powerful "Evil Faction" threatens war, Elara and her friends stumble upon a forbidden text that challenges the academy's core teachings.
The line between law and tyranny begins to blur, and Elara's suspicion crystallizes during a ferocious mountain storm when she witnesses Kaelen perform a feat of boundless, cost-free magic that defies every law she's been taught. Now a witness to the magical world's ultimate taboo, Elara and her friends must act. In a desperate race against time, they attempt a reckless data breach on the Adjudication Council's highest security server.
The alarm is instantaneous, and the chase is on. The Stone Invitation culminates in a desperate flight through the mountain's forgotten tunnels, where Elara must break the law she just learned to save herself. This opening installment sets the stage for a world teetering on the brink of war, where the only person who can challenge the ultimate fear of "unlimited power" is a first-year student running on an empty essence gauge.