When Sarah Jane Smith returned from her unexpected stop in Aberdeen, she might have thought life would return to normal, or at least as normal as it had been before she ever met the Doctor.
It did not.
Sarah Jane quickly realised she needed help. She was not above asking for it when necessary, and she knew exactly the place to contact.
Thus, when Sarah Jane Smith discovered a hive of Muktaarak demons in her garden, she rang UNIT. When her investigations at a university turned up a stray Sontaran successfully posing as a history professor, she contacted UNIT again. All in all, she encountered so many oddities that the Brigadier eventually suggested she come to work with them on an official basis, get paid for her efforts, and simplify everyone's lives.
She did, and it proved an excellent fit.
In the beginning, Sarah Jane and the Brigadier regularly referenced the Doctor. They both thought that at any moment, the grinding racket of the TARDIS would again fill the corridors and out of the door would pop his familiar grinning face. The obvious exception being if he had changed again, of course.
Months drifted past, and this did not happen. The Doctor became a lesser topic.
Certainly Sarah Jane still missed him, thought she always would a bit, but his continued absence hammered home the fact that they never were going to settle down, marry, have children. It had been a vague fantasy, never consciously expressed but somehow lurking in a back corner of her mind, until one ordinary day when she was thinking of her life as it stood now. She laughed at the ridiculous fantasy, a bit ruefully since she would have thought she was beyond such childishness, and went to consult with the Brigadier about their latest adventure.
She came away finding herself worried about him. He had seemed quieter than usual lately. Polite, yes, as always, but withdrawn and a bit sad. Today, that impression was more pronounced. Puzzled, Sarah Jane wandered back towards her office. She nearly bumped into someone and looked up to apologise.
'Oh! Sergeant Benton!' she exclaimed. 'I'm so glad to see you!'
Her enthusiasm seemed to take him aback a little, and well it might since they had seen each other less than three hours earlier. Nevertheless, Benton smiled gallantly and responded, 'And I you, Miss Smith.'
'Sarah,' she briskly reminded him before rushing on. 'I don't suppose you would happen to know if anything in particular is troubling the Brigadier these days? He seemed a bit down just now.'
'Ah.' Benton bobbed his head. 'Not to be gossiping, but I know you won't spread this around. I overheard him on the phone the other day. He and Doris aren't seeing each other any more.'
'So he's depressed,' Sarah Jane mused. 'Well, that's understandable. I know the feeling, but I'm sure he'll be fine. Thank you, Sergeant.'
She beamed at him and, flustered, he muttered a reply before continuing on his way.
Yes, Sarah Jane thought, she did understand how the Brigadier felt. She and the Doctor had, essentially, stopped seeing each other. Then there had been Harry, dear Harry Sullivan who would always be a great friend but never could become anything more.
She did not admit to the Brigadier that she knew of this change in his circumstances. A private man, he kept himself to himself in personal matters. She did take care not to mention Doris's name and to do little things to help lift the Brigadier's mood.
She found thinking about him more and more during this time. The Brigadier, she thought, was never the sort of man to strand a lady in Aberdeen. He would quite properly show her home or arrange for a reliable escort. He was the sort who could and would marry, settle down, and have children. Though he phrased himself 'old fashioned', Sarah Jane thought there was a great deal to be said for his brand of manners, his courage, resourcefulness, and kindliness. There was a great deal to be said for men like the Brigadier in general.
Yet she mused increasingly about this man in particular. She knew she would approach him one day with the results of these considerings. Not yet, though, not quite yet. It was too soon after the end of his relationship with Doris.
So more time drifted by. Sarah Jane became increasingly certain of the feelings she wanted to pursue. Occasionally she fancied she saw the Brigadier looking at her in a speculative way, as if he could read her thoughts, but those moments always passed quickly. Until one afternoon.
'No Sontaran sightings since the uni, then?' Sarah Jane asked in high hope.
The Brigadier shook his head. 'No, although we did check on what turned out to be a false alarm reported by Harry Sul-' He stopped abruptly.
'Harry Sullivan, you mean,' Sarah Jane said steadily.
'Well, yes.'
'You can mention his name around me, you know,' she pointed out. 'I know that once, for a while... Well, no longer. I'm very unattached.' And she looked the Brigadier in the eye.
He cleared his throat. 'I had thought that you and Harry might...' He trailed off delicately.
Sarah Jane laughed. 'No, no, Harry and I are just friends. We both know it could never work out between us that way.'
The Brigadier nodded, and now a faint smile tinged his lips. 'I see. In that case, Sarah, would you happen to be free for supper this evening? I believe we can find a lot to discuss.'
She smiled back and placed her hand atop his. 'I'd be delighted to join you, Alastair.'