The season 4 of the series Rookie Blue tells the story of five young people who graduated with honors from the police academy, and came to work in the police station. They have to forget all the things they have been taught in the offices of the Academy. On the streets of the city they do not need a theory here it takes practice. Recruits have already shown their ability to combat crime, but this time they will have to face this danger. Now, everything depends on the knowledge and skills that the protagonists have acquired during previous seasons. The slightest mistake can cost the life of young people. New investigation of more serious crimes, will make these recruit cops a professional police.