Samuel is a huge Spanish Slug with a vision: to slime the full length of the El Camino from St Jean Pied de Port to Santiago de Compostella, and then, things still going well, on to Finisterre. Fully supported by his slau, Sally, he sets out with his tiny backpack, only to encounter challenges at every turn.

If it's not stick carrying people, it is the weather, dangerously careless boots and cyclists, snorers, temptations and temptresses, and, most dangerous of all, operatives working hard for SPECTRE to see to it that Samuel is unsuccessful in his plan. Samuel's slau too, has inadvertently complicated matters by defeating a high ranking Spanish politicians' daughter in a competition.

But Samuel finds support along the way. There are El Camino Miracles: fellow pilgrims who care, hospitality beyond expectations and good wine served will all pilgrim meals. But most of all, British Ministry MI10 take a keen interest in seeing that Samuel is successful in his mission, and will uncover a vast conspiracy that could threaten the entire slug population.

And just off the path, a guardian angel is watching carefully.

Colourful characters appear along the way, some with an understanding of Samuel's language, Arion Vulgaris, which is sprinkled throughout the verses, and some without. Some good and some not as helpful, these characters are based on real people the author encountered when he walked the El Camino with friends and family. Samuel too was also spotted on the track by the author, not far from Larrasoana.

The story follows Samuel's adventure along the Way of St James, from posing his idea to Sally to settling back at his home in Seville. There are sumptuous illustrations, explanatory excerpts from the Arionspeak dictionary and biographical notes for all of the main characters.

Samuel is certainly not a common garden slug and his El Camino is far from typical.

With the odds stacked against him, can Samuel finally find his way?