Sister from the multiverse

". . .you and your single mom live an ordinary life sure, she's always been a bit secretive about her job, but it's none of your business. That is, until a girl arrives outside your school one day claiming to be your long-lost sister and from a parallel universe! Does your mom's top-secret research at her science lab have something to do with it? And can you and your sister figure out how to unite your broken family and stop an evil scientist from using your mom's technology to take over the multiverse?"--Provided by publisher.