A mechanic's apprentice recovers a magical artifact, which makes him a target for demonic soldiers and a bounty hunter, and struggles to escape to a safe haven without being tracked there or losing the artifact.

Maybe just to make it a little bit more active:

After a mechanic's apprentice recovers a magical artifact, he becomes the target of both a bounty hunter and demonic soldiers, he has x amount of time to get the artifact to a safe house before the bad guys do x to him.

So it's a magical MacGuffin. As Richiev inquired, what does it do? More importantly for the logline what is the apprentice supposed to do with it? The protagonist's actions are described in reactive/negative terms (escape...don't lose). What is the flip side to that: the proactive, positive objective goal he pursues with this MacGuffin?

This seems to be a riff off the tale of the "Sorcerer's Apprentice". If that is the case, then does not this story also entail the archetypal theme embedded in the tale, the immaturity of character that leads to misuse of power and the unintended, baleful consequences that follow? The apprentice mechanic does have a character flaw, doesn't he?

Also, what does the artifact do? such as: "When a mechanic's apprentice discovers a magical artifact that turns old cars into new sports cars..."