The 2401 break-in at Daystrom Station, where Picard's allies found what the Changelings had stolen and woke a synthetic body holding Data's mind.
In 2401 Picard's allies needed to know what the Changelings had taken from Daystrom Station. Geordi La Forge got his old friends inside the facility, and they made their way past its security systems, including a hologram of the villain Moriarty.
Inside they found that Picard's original human body had been stolen, a clue to the Borg plot. They also found a synthetic android body built by Altan Inigo Soong and woke it. The android held the minds of Data and his brother Lore, among others.