A time loop or temporal loop is a plot device in which periods of time are repeated and re-experienced by the characters, and there is often some hope of breaking out of the cycle of repetition. Time loop is sometimes used to refer to a causal loop; although they appear similar, causal loops are unchanging and self-originating, whereas time loops are constantly resetting: when a certain condition is met, such as a death of a character or a clock reaches a certain time, the loop starts again, with one or more characters retaining the memories from the previous loop. Stories with time loops commonly...