What have you been doing far? Without knowing it is hard to make suggestions. However some somewhat universal things to do;
Find the thermocline using your sounder. And yeah, look for fish with the sounder as well. Focus on areas that have quick depth transitions, drop offs. S curve over those contour lines.
With a plug that floats, I wouldn't send it too far back before clipping to the rigger if you are dropping down 35, 45, 55ft of cable but letting out 50ft of line before clipping in. This will have your plug running too high. After marking fish or dialing in the thermocline, say it is at 45ft. Only put out 15-20ft of line line before clipping to the rigger.
Remember to vary speed. And stick a piece of worm on the hook of the plug as well. Not too much to impede the action. Oh yeah, and as others mentioned, try using flashers and spoons or smaller hootchies as well. Perhaps try downsizing and go after some kokanee. Small flasher/dodger, wedding band with worm or shrimp and bob's your uncle. Again hard to know what to suggest if we don't know what HASN'T been working so far.
There are tons of fish in that lake, should be decent action. Get out there at first light and fish for a 2-3 hours then head in for breakfast. Get back out at dusk FOR SURE and fish til dark.
Keep mixing things up, depth, speed, lure size, lure colour etc. 5 days and 1 dink smells of not adapting and adjusting. GOOD LUCK!