# Adventure Summary
A mysterious magical signal has begun pulsing from deep beneath the **Mwangi Expanse**. Scholars at the **Magaambya** have traced the source to the legendary **Heartwood Vault**—a forgotten elven fortress believed lost beneath the waters of the **Vanji River**.
More than three thousand years ago, the **Emerald Legion**, an elite order of elven guardians, constructed the vault to imprison a devastating magical fungal plague. Rather than risk the corruption escaping into the world, they sealed themselves and their fortress away, disappearing into history.
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Now the ancient wards are failing.
Strange emerald light glows beneath the river each night. Wildlife has become twisted and aggressive, luminous fungi spread through the jungle, and the magical pulse grows stronger with every passing day.
If the vault's containment finally breaks, the blight could spread across the Mwangi Expanse with catastrophic consequences.
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The heroes are dispatched to investigate the disturbance. Their journey leads them through the dangerous Vanji jungle, into flooded ruins untouched for millennia, and past the deadly defenses left behind by the Emerald Legion.
As they delve deeper into the vault, they uncover the Legion's final sacrifice, battle creatures transformed by the ancient plague, and piece together the truth behind the fortress's disappearance.
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In the end, the party must choose how to stop the corruption. They can restore the vault's failing containment, destroy the source of the blight, or risk unleashing an ancient plague upon the entire Mwangi Expanse.