Eating the Realities.
Dr. Strange is a hard character for the age group that this title is aimed at. Some of the concepts around him are difficult to understand for the younger people. They do a nice job in this one of not getting to deep into the alternate realities and magical incantations.
There's a great (short) explanation of how Dr. Strange got to be the Sorcerer Supreme.
The Doctor recruits Spidey to help him out in stopping the Zakimiya from eating the fabric of the realities. He gives Spidey some special abilities that allow him to repair the fabric of the realities and to help him stop the Zakimiya. The Doc gets Spidey to extenuate his already sassy attitude which the kids will get a kick out of.
Would have like a little more action thru the middle, but over all it's a good read and one the kids will like... or should like anyway.
If you can find a copy around, it's worth picking up.