''Another visitor? Stay a while. Stay FOREVER!''

An assignment is received in TheTeaser. A planning session is held (AvengersAssemble). Then comes TheCaper or TheCon, using a MasterOfDisguise and an ATeamMontage. The resolution is as close to end of TheTag as possible.

At about the 40-minute mark, there is a PseudoCrisis.

The trope takes its name from the series ''MissionImpossible'', whose Impossible Mission Force did one of these every week. The trope quote comes from the C64 game ''Impossible Mission'', which actually wasn't all that Mission Impossible-ish, oddly enough. (However there were ATARI and ZX-Spectrum ports of that game, which were [[UnwinnableByMistake Unwinnable]] due to a bug, hence carrying its name for good reason — although unwanted)
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Examples:
*Despite its few episodes, ''{{Firefly}}'' did two of these, in "Ariel" and in "Trash".
*Mercilessly parodied in the ''WhoseLineIsItAnyway'' game "Improbable Mission," which had agents given missions involving high stakes but ordinary tasks, such as doing laundry or mowing the lawn.
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