Star Trek: The Next Generation – Masks [7.17]

The Enterprise encounters some sort of strange phenomenon that causes various parts of the ship to be slowly transformed into a copy of a long dead ancient civilization, while Data becomes possessed with multiple dead personalities from this civilization. 

Star Trek: The Next Generation – Thine Own Self [7.16]

Suffering from amnesia after being Injured in an accident, Data wanders into a pre-warp village and inadvertently exposes the local population to radioactive rocks.  He races to find the cause of the people’s sickness before lives are lost, but at the same time comes under suspicion for causing the problems himself. 

Star Trek: The Next Generation – Gambit, Part I [7.4]

Riker and the crew of the Enterprise find evidence that Picard has been killed while on leave exploring some archeological ruins.  Investigating further, Riker is captured by space pirates who are seeking particular Romulan artifacts, but is shocked to discover that Picard is amongst the pirate’s crew!