In hollow lands - Sophie Masson

When twins Tiphaine and Gromer are lured from their peaceful home into the strange world of the powerful, magical korrigans, it is the beginning of an extraordinary adventure and a terrifying ordeal ... How will they break the spell of their enchantment, who will help them? But Tiphaine's bright mind sees that not only korrigans may discover hidden powers within themselves.

Meanwhile, in the human world, a young squire named Bertrand du Guesclin is fighting in the wars against the English. Until one day he finds himself in a wood where a dangerous presence seems to hover, a presence that will transform his life ...