A recent fascination with Netherese magic. Or some other obscure school of wizardry. If she's your mother, she ought to know how insufferably distractable you are when you've found something to fixate on.

The obsession led you to the artefact, the artefact to the curse, and now you're off with a merry little band of adventurers to unravel the whole thing in the name of knowledge and power. Simple.