A jump starter was used to get the car running. Got the car back from the service dept. yesterday aft. After extensive diagnostics, the problem could not be pinpointed. The car's computer was updated, however. The technician was perplexed that he could not identify the gremlin that caused the battery to completely drain. He told me the car has a fail safe system that is supposed to prevent a complete battery drain. Apparently it didn't work.
I am now concerned this will happen again, and I will get stranded. Have decided to join AAA for piece of mind.
As an aside, for those of you who have a Fusion, pls. read page 164 of your owner's manual to identify how to release your transmission from park if you ever have a similar circumstance. A big thanks to Economic Sinkhole for that little gem of info.
Happy motoring everyone.