I'm going to tell you something I wish someone had told me years ago: A child who is giving up his nap and has gone several days without one will suddenly be unable to fight it any longer and will fall into a deep sleep wherever he happens to be at the crashing point. A very deep sleep. This may be in a cute position on the carpet or couch, but may also be out of sight-- under the kitchen table, behind the couch, or in the toy box.
So, before you search rooms in a growing panic, run outside with your heart in your throat screaming your child's name at the trees, begin to imagine all manner of horrors, or reach for the phone to call the police...look under that pile of throw pillows, behind the door, under the bed, and in the cupboards. You may just find a very sleepy toddler.