The moon's road is a path that forms on the surface of the ocean when moonlight on the water seems solid, indicated by a subtle green flash. These moments occur randomly, and once they do the moonlight becomes solid on the water, forming a crystalline, glass-like path that leads out to sea. The path begins to dissolve once the moonlight moves from the correct position on the water, causing the moon's road to crack and become riddled with holes until it is completely gone.
The moon's road can only be crossed by those with faerie blood. Half-fey are also able to access it.
Julian Blackthorn, Emma Carstairs and Cristina Rosales followed Mark to the moon's road and caught up with him near the Gate, using Cristina's medallion, which was enchanted with faerie magic, to use the road despite not possessing faerie blood. They then encountered the Guardian of Lir's Gate, a phouka who collected a toll from each of them in exchange for a promise.
Once the Gate opened, the moon's road began to disappear and the Shadowhunters crossed through the Gate just before it completely dissolved.
- Despite all the entrances to Faerie being closed due to the Cold Peace, the moon's road remained active.