Star Trek the Next Generation: The Best of Both Worlds

Stardate 43989.1. Eighteen months after the USS Enterprise's initial encounter with the Borg (a collection of half humanoid, half machine beings) the Federation is again threatened.

Insufficiently capable of defending itself against the overwhelming invasion force, Starfleet assign Borg expert Lieutenant Commander Shelby to the Enterprise.

Picard is abducted by the Borg who assimilate him into their consciousness in an attempt to pre-determine Starfleet tactics in response to their invasion.