In this episode, as Data contemplates the impending marriage of his friend Keiko Ishikawa to Transporter Chief Miles O'Brien, he learns about the peculiar minutiae – such as last-minute jitters and ballroom dancing – that surround human nuptials.
At the same time, he investigates the apparent death of the Vulcan ambassador whom the Enterprise was ferrying to the Neutral Zone in order to conduct treaty negotiations with the Romulans.
Transporter Chief Miles O'Brien (Colm Meaney) and civilian botanist Keiko Ishikawa (Rosalind Chao) are about to be married, and Data (Brent Spiner) has been asked to give the bride away.
After Keiko calls off the wedding, Data seeks advice from Geordi (LeVar Burton) and Counselor Troi (Marina Sirtis).
Meanwhile, the Enterprise is taking Vulcan ambassador T'Pel (Sierra Pecheur) to a secret meeting with a Romulan ship inside the neutral zone.
[3] They praise masterful acting by Brent Spiner as Data throughout the episode, offering what they call a "Pinocchio perspective" on the plot.
[11] "Data's Day" was released in the United States on September 3, 2002, as part of the Star Trek: The Next Generation season four DVD box set.