Season 1, Episode 3:
An ancient sea monster attacks two lifeguards in a municipal swimming pool while a mother makes a terrifying discovery when her utility room starts to flood. Cutter is desperate to make Lester realise the seriousness of the situation, but infuriatingly Lester remains optimistic that this problem will disappear just as quickly as it arrived.
Yes, the monsters in "Primeval" were real and once stalked the earth. Read more about the water-dwelling creatures featured in tonight's episode here.