Malfoy's magic has run wild. But though wild magic is unpredictable and greatly feared, Harry's damned if he's going to let Malfoy rot in St Mungo's while they work out what to do with him.
The introduction is intriguing, so I was disappointed when I found out how ridiculous the solution was. Of all the Drarry stories about dealing with the hawthorn wand's loyalty problem, this is definitely the most stupid one.