Moonlocket by Peter Bunzl is the second book in The Cogheart Adventures trilogy. Lily and Robert are trying to figure out what the Moonlocket is, but they get a rude awakening when secrets from Robert's past come to light.
This is a story that can be read as a stand alone, though there are mentions of instances from the first book, it will in no way ruin this story for the reader.
I thought this was a fun, yet sad story at times. I love the characters and the world the author has created.