PlayerGui is not a valid member of Player?

hev=true
on=false
mouse=game.Players.LocalPlayer:GetMouse()
plr=game.Players.LocalPlayer
char=game.Players.LocalPlayer.Character
--variables--
if hev==true then
	plr.PlayerGui.ScreenGui.Frame.left.Visible=true
	mouse.KeyDown:connect(function(key)
		--do something
	end)
end

error: PlayerGui is not a valid member of Player

Script 'Players.Player1.Backpack.LocalScript', Line 8