All 18 episodes.

In line with the phrase "I will meet you in 25 years from now" by Cooper's investigator in the final story of 1991, it is a splendid flow that the production of a new series will be released in 2016 after 25 years.

Since the start of the broadcast is 2017, it did not strictly match for one year, but I'd like to expect the work itself to be wonderful.