Marina Quiroga, a daring upper-class girl with a detective's soul, sets off to catch the serial killer that has been terrorizing her town with her faithful butler Hector's help.
When Cassandra's motocycle breaks down while she, Gersinho, and Leide are coming back to Sao Paulo from a math competition, Leide calls Cassa ndra's mechanic father. A painful confrontation with the past follows.
