The fourth and last part of the series is better than [Rec]³: Génesis and goes back to the story of the first 2 parts. It is being scary and claustrophobic again but it is no found-footage movie anymore. You could be tired of the procedure of the movie, which is almost the same as in the first 2 parts. If you're a fan of this saga watch it!
Synopsis - SPOILER ALERT
Again are Special forces from the Spanish army sent to the contaminated apartment building in the city-center of Barcelona. Their mission is to rescue the reporter Angela (Manuela Velasco) (who we already know from the first two parts) and to destroy the building. After the mission was successful, Angela wakes up chained to a bed on a ship in the high seas. It turns out that the ship is a quarantine ship to prevent the virus from spreading further. However, head physician Dr. Ricarte (Héctor Colomé) said, that she was not infected with the virus. Meanwhile, the doctors noticed that their test object, an infected monkey, had been released and attacked and infected the ship's cook, who contaminated the food. Therefore, most of the crew and guards got infected. After Ricarte failed to create a cure, he decided to initiate the ship's self-destruction process to prevent the virus from spreading.