The Incredible Aunty Awesomesauce

Sam Aushumness, sixteen, orphan and high school outcast, meets his long-lost aunt at his parents' funeral-or the woman he thinks is his aunt. It turns out that she isn't his aunt, isn't from around here, and isn't even from this galaxy. It seems the person masquerading as his aunt is a refugee from a faraway world, and she's being pursued by a small band of mercenaries who have been hired to bring her back dead or alive-preferably dead.
Secrets have to be kept, and only Sam and his girlfriend, Kym Kim, know who Aunty Aushumness-nickname Aunty Awesomesauce-really is. However, the secret soon gets out, and soon the mercenaries, the police, and every branch of the government are on the hunt to find Aunty Awesomesauce, what she knows, and what secrets she carries. Aunty A, though, isn't one to back down from a fight, and when push comes to shove, the mercenaries find out how bad she can be.