Split into two parts –one a season finale and the other a season premiere—“Time’s Arrow” opens with the investigation into why Data’s head was found in a mine shaft on Earth that is over 500 years old. Data of the present appears unaffected, but despite efforts made by the crew of the Enterprise to keep him that way, “history must be fulfilled.”
“Time’s Arrow: Part 1.” Star Trek: The Next Generation. Paramount Television. 13 June 1992.
“Time’s Arrow: Part 2.” Star Trek: The Next Generation. Paramount Television. 19 September 1992.