BE90 pilot reported an electrical failure during departure climb resulting in a return to the departure airport.

Narrative

I was on an IFR flight plan ZZZ to ZZZ1. Approximately 4 minutes after takeoff; in VMC conditions; while climbing through 7000 ft. direct to ZZZZZ the autopilot disconnected. Shortly thereafter I noticed both engine fuel flow gauges dropped to zero and both torque meters dropped to zero. Anticipating engine failure; I contacted ATC and requested a heading to the closest airport. I retrieved and followed the checklist. ATC assigned me a heading direct to ZZZ. Shortly after turning to the heading; I experienced total electrical failure and lost all primary flight instruments including all GPS's. My back-up VSI; attitude indicator and Airspeed indicator were functional. I had intermittent radio transmission; however I lost all radios approximately 2 miles from ZZZ. Once I had ZZZ in sight I attempted to put the landing gear down but it was not functioning. I followed the checklist for landing gear extension; however; before completing the landing gear extension I had electrical power for a few seconds. Using the electrical power I was able to extend the landing gear and flaps. I was able to land without further event and taxied to the Ramp under the aircraft's own power.Upon inspection; it appears that; unbeknown to me; someone had spilled liquid near the Cockpit Area and the general consensus is that the liquid ran through into the electronics located under the floor. The liquid caused the short of the electrical system. The aircraft has been taken to Maintenance who are performing a complete check of the electrical system.