Lightclock Amulet

Lightclock Amulet enters the battlefield with four hour counters on it.
Whenever a white creature or a Plains enters the battlefield under your control remove an hour counter from Lightclock Amulet.
As long as there are no hour counters on Lightclock Amulet white creatures you control get +1/+1 and all Plains have "{t}: add {1}{w}"