Plastic cap to my coolant fell into the front part of my 2003 Honda CRV?

The plastic cap to my coolant fell into the front part of my 2003 Honda CRV? - 1

Added (1). & I can't find it in there anywhere though I know it's in there somewhere. Should I be worried about it harming my engine or melting and starting a fire?

Get it and put it back on the coolant. However, its no big deal. Find another way to cover the overflow reservoir, like aluminum foil and a rubber band until you can get another cap. You may be able to get one off an old car at a junk yard. The fact that the cap is plastic indicates its not on a very hot pressurized part of the cooling system.

Then dig it out or go buy a new one.

Plastic floats. Carefully feed a water hose down where the cap went and be careful to not aim spray at the motor. Run a stream of water over the shield under the engine and watch where the cap goes when it floats out.