Math is not ten-year-old Zaritza's best subject. When her teacher, Mr. Phinney, offers extra credit to whomever takes the class ferret, Bandito, home over the weekend, she jumps at the opportunity. Unfortunately, taking care of this particular animal is as boring as school itself. All it does is eat, sleep, and lick itself. So when Zaritza accidentally leaves Bandito's cage open and the ferret goes missing, she blames everyone else, including her three-year-old sister. And her excuses get bigger and bigger. But when her mom finds out that there is a ferret on the loose, Zaritza better find her class pet fast!