'One' has five friends played by Rosin, Vishnu, Vinod, Devika and Saumya, playing characters in the same names. They appear as five techies by profession who likes to hang out to interesting and tougher places when ever they get a holiday. And this time, they head to a reportedly creepy manor on a hilltop, a few kilometers away from the city. They, for the first time, bring with them their boss (Jagadeesh), who is struggling to get over the recent loss of his wife Uma. From the first minutes on the house, we are let known that this is a spooky house where none will dare to stay. But the youngsters surprisingly decide to walk in, live in the dusty, hardy lit rooms, just with no convincing reasons.