No compression-next move?

I know this is a Gen3 Hemi, but it should be the same for all motors:
Car was idling in the garage, suddenly died. Not electrical or fuel. Removed valve covers, everything is moving. Zero compression on all cylinders. Does this sound like chain or sprocket slipped?

It's a ***** to take off the front cover on this motor because it has a motor plate so I have to support the motor with a cherry picker. Sounds like the front cover needs to come off though.

Once again, the cam is turning but the valve timing seems suddenly way off.