Author's Notes:
Four/Romana. Originally posted to AO3. Title from the song of the same name.

Never promise what you can't be sure of.

“It can’t last forever, can it? You and me,” said Romana.

“Of course it can,” said the Doctor, recklessly.

“Nothing lasts forever. Didn’t they teach that in your day?” She was sleepy and melancholy, a dangerous combination.

“I don’t know,” he said, holding her closer. “I didn’t pay attention.”

“Think about it,” she pursued. “The universe itself will end, so each part is contingent. Including love.”

“How’s this,” said the Doctor. “If we ever get separated, we’ll meet up at the heat death of the universe. Then we’ll go back and start all over again.”

“It’s a date,” said Romana.