Scarlet from Gold — Jeffrey Quyle

A boy without memories- only a compulsion to find an unknown lady who is hundreds of miles away: that is the beginning of Marco's adventures in “Scarlet from Gold” the third book in the Alchemy's Apprentice series.
Marco lands at a small port and knows he has to travel a great distance to find Folence. But his journey is made easier, and the nature of the journey is changed, when a group of pilgrims take him under their wing and travel with Marco to Compostela, the great holy site that sits astride the road Marco is bound upon. The journey proves entertaining, thoughtful, and unexpectedly enlightening.
When he completes the trip, after passing through an unhappy encounter with Mirra, Marco reaches his goal and recovers his memories, only to discover that another extraordinary challenge awaits him, and he'll be accompanied by a supernatural companion as he attempts to return to the underworld while still alive!
Marco returns to scenes of past adventures, meets old friends, and undergoes new challenges as he moves along the trail of discovery that will lead him towards the conclusion of the Alchemy's Apprentice series in the final book in the series, “The Southern Trail.”