2013 Regal, ~ 10,000 miles, will not start and has no electrical power at all.

What is your question?

The car ran fine two days ago. Parked it in my garage Friday afternoon, Sunday evening it was dead! This happened once before, dealer had to tow it in and was able to jump start it at the shop. Something electrical appears to either stay on or turn itself on and completely drain the battery. Any suggestions?