From the mountains of bavaria to the secret tunnels under king Ludwig Ii's castles, no one is safe when they search for The Secret Crown. Hidden among the crates in a recently discovered World War II bunker are documents...From the mountains of bavaria to the secret tunnels under king Ludwig Ii's castles, no one is safe when they search for The Secret Crown. Hidden among the crates in a recently discovered World War II bunker are documents stamped with an elaborate black swan, the insignia of the murdered king Ludwig Ii.