Children of Invention (2009)

After being evicted, hardworking single mom Elaine Cheng (Cindy Cheung) tries to maintain a normal life for her children. Elaine juggles a number of jobs, including working for a questionable pyramid scheme. When Elaine doesn't return home one night, nobody knows the kids are home alone, and they are left to fend for themselves. As the days pass, her son, a budding inventor, realizes he needs to come up with a plan to take care of his little sister.