You show four of a kind.  During subsequent counting a different card turns face-down.  Following this phase, the backs change from blue to red and then to silver.  
 
Because of the last change you are able to explain "it's all done with mirrors."  
 
There are no difficult moves and no complicated sleights.
 
Condition Notes:  This trick has never been used; however, due to storage, the “mirror” backs have caused some minor wear to the faces of the gimmicked cards (see photos). The accompanying deck of blue Aviators is brand new.