As the Enterprise heads into the nebula (which is of much higher density than past examples they've seen) to examine a class-M planet they've detected, Data asks many people for advice on whether to pursue a relationship with Jenna. Guinan says she doesn't like to give advice on first relationships. Geordi says his advice is "find someone else to give you advice." Troi cautions him to be very careful, as Jenna could really get hurt, but then says that if he tries, he'll have to be more than the sum of his programming. Worf tells him to "conquer," not "pursue," but cautions that he doesn't want Jenna (who's in his section) mistreated. Riker tells him of wonderful rewards, and tells him to go for it. After all that, Data appears at Jenna's door with flowers. His initial attempts are somewhat...unsubtle...but Jenna realizes he's trying his best and lets herself be drawn in.
While Jenna tutors Data in the finer points of a relationship, the Enterprise crew begins to discover a few problems. At first, they're minor: Data's cat got out of his quarters and shouldn't have been able to, and Picard finds his ready room's computer console under his desk and in pieces. Things get stranger still when they finally reach the location of the class-M planet, and find nothing at all-especially when moments later, it's there again. Suddenly, there's a brief bout of atmospheric decompression in the observation lounge, but no apparent hull breach. Once standard pressure is restored, they go have a look and find no trace of what caused the damage, except for a few tiny electric current in the windows, which are often evidence of a subspace distortion.
After Jenna gets a little unnerved by Data's precisely calculated solicitousness, and then his forced and deliberate "lovers' quarrel," Picard decides enough is enough with these incidents (since more have occurred, but none causing any injuries yet), and decides to analyze them from outside the nebula. Unfortunately, before they can leave, a few more problems occur: a science station blows out, then an engineering station. A structural failure is detected between two decks, but when Geordi sends out a team, he quickly finds that one of the members fell halfway through the deck, which then resolidified, killing her instantly.
Data's figured out the problem: the high density of dark matter has caused minor gaps in space, which are drifting randomly and causing major havoc whenever they "blip" into this space. Sensors can be tuned to detect them, but only at ranges close enough that the ship could never get out of the way in time. Picard, in a shuttle, flies ahead to do so. The shuttle is eventually destroyed, but Picard is rescued and they got far enough out that they make a successful run out of the nebula. Finally, Jenna realizes that she's just repeating her old patterns (breaking up with one unemotional man only to get together with another), and severs her and Data's relationship.