Smart Virus

A smart virus is born, but it lacks the DNA needed to successfully replicate and create new viruses with smart capabilities. That DNA is found in a master cell, but to find it, you must first go through and infect a series of other cells to obtain the proteins needed to locate the elusive master cell which releases a signaling chemical through diffusion. Track down the origin of this chemical and you track down the master cell and achieve replicative success.