The Enterprise races to a starbase to save the life of a young boy who has inadvertently eaten poison for reasons that ... well, are perhaps a little more contrived than they need to be. (I've always found the initial premise of the sick boy to be the episode's most obvious weak link.) This emergency is halted, however, when a homing signal in Data's brain is triggered and he takes over the ship, diverting it to a nearby planet. Data's takeover of the Enterprise is depicted with some memorable opening-act action that proves just how dangerous Data can be when his human qualities are disabled and he becomes, simply, an unstoppable machine. (His multi-dozen-digit lockout code of the computer — recorded in Picard's voice — is classic.)
"Brothers" is like "Family" with a plot. Coming on the heels of "Family," the thematic similarities are interesting, even if the storytelling method is completely different. (For one, we're dealing with the family roles surrounding an android who has no emotions; for another, we have a more traditional Trek structure, with action and plot.) When Data's conscious mind is reactivated, he finds himself in the lab of his creator, Dr. Noonien Soong, long believed to be dead. Not too long afterward, Lore walks through the door, having also followed the signal home (and proving that "Datalore" was merely the beginning of their arc). With both Soong and Lore, we get two surprises where we might've expected only one; the story brings the entire Soong "family" to one household to tell a tale we didn't envision when the hour began. In that telling Soong reveals he's dying.
Brent Spiner is superb in three roles of characters who are very different and yet vitally connected by the intimate history they share. We see here that Lore is not simply "evil," but a tragic victim of his own existence gone awry. No one is more regretful of that error than Soong, who would've liked nothing more than to fix Lore, if only he'd known he'd been reassembled, and if only there were enough time. Rather, Soong has brought Data here to give him the gift of basic emotions.
In the final act the story pulls the ol' switcheroo — which, I suppose, was inevitable — with Lore disabling Data and taking his place so that Soong installs the emotion chip in Lore's positronic brain. This seems to have the effect of making him even more unstable. The way Lore lashes out at his father makes you wince with sympathy; here's a man who had good intentions but felt forced to shut down Lore like a failed project, and that project now resents him for it. And now the father's failure for his first child prevents him from realizing his dreams for his second. (Note: No comments about B-4 will be entertained.) It may be with a sci-fi twist, but human feelings are still the point here. The message of the final scene all but guarantees Data and Lore will meet again, and seems to ponder what they might ultimately mean to each other.