I have a 2007 Lexus ES350 with about 185K miles on it. I've owned it for about 14 months, never had a problem.
Over the past couple of days it was sitting parked in my garage. I'm not sure, but the interior dome light could have been left on. When I tried to start it today, there was nothing. No response, no lights, no clicking. Absolute silence. Even the electric-powered door-locks and trunk-opener wouldn't work.
So I tried jumping the car. As soon as I connected the cables, all the electrical systems came to life: A/C, Headlights, dash lights, beeping, etc, etc.
However, when I tried to start the car while the cables were connected, it wouldn't start. I could hear the electrical clicking, but absolutely no turnover. Here's a short video: https://photos.app.goo.gl/E34619ZJL8JJAvV3A
Would a battery replacement likely fix this? Or is it something more serious?