Clues

TNG Season 4 Episode 14
Air Date: February 11th, 1991

While surveying the Ngame nebula the Enterprise sensors picks up the presence of a class M planet. They set course to investigate but a wormhole appears and the entire crew save Lt. Cmdr. Data is knocked out. When they come to, Data says they were out for less then a minute, but the Enterprise is almost a day away from the class M planet.

Data suggests that they launch a probe to investigate to avoid risk that the wormhole introduces. The probe shows that the once class M planet is now a gas giant. Other things start occurring that makes the crew suspect what really happened. Things like Lt. Worf's wrist showing evidence of being broken or Doctor Crusher's flowers that she just put in an incubator being fully developed. Most of all, it is clear that Data is lying about it.

Finally getting the truth from Data once they arrive back at the class M planet, they find out that the race that lives there was going to destroy the Enterprise to protect their privacy and that the crew decided to have a memory wipe and to think the wormhole took them a day away. This is what the aliens would normally do but since Data is an android he was unaffected. The problem is they left too many clues and Human's are naturally curious.

Captain Picard suggests that they try the plan one more time only this time they will remove the clues. The aliens reluctantly agree and this time it works.

Quotes

"Do you believe him? I want a frank answer, Commander." - Captain Picard
"Not for a second." - Lt. Cmdr. La Forge

"Clues were left behind that suggested a mystery. And to many humans, a mystery is irresistible. It must be solved." - Captain Picard