 In the future, a time travel agency offers "The Time Safari", where client may kill animals like dinosaur, but specifically selected by the team, in order to not change the environment and consequently past. During one expedition, the traveler becomes scared with the huge dinosaur and leaves the protective path, shooting and stepping on the woods. When the team returns to their base, they realize that future has changed, and a further investigation showed that client stepped on a butterfly, with drastic consequences to mankind.