First three episodes from the reimagined version of the 1970s sci-fi classic. After a long and violent war between mankind and the Cylons, robots invented by humanity that eventually rebelled against human rule, the Cylons disappear and haven't been seen for 40 years. When they return, destroying mankind's defences in minutes, the last surviving humans rally round the Battlestar Galactica and head into deep space, in search of Earth, the fabled homeworld of the human race. In '33', the Cylons have managed to lock on to the Galactica's signal, and are emerging from hyperspace every 33 minutes to attack. Is there a traitor on board? In 'Water', Boomer (Grace Park) wakes up after having planted a bomb in the ship's water supplies. Could she be a Cylon in disguise, and not know it? Finally, in 'Bastille Day', Apollo (Jamie Bamber) has a plan to use prisoners in the fleet on the dangerous mission to gather water from a hostile planet.