Walter hummed absently to himself the tune that had been haunting him ever since he had gone with Olivia and Peter to Edina.

Hard artichokes rarely keep, Norwegian elephants, Singapore sleeps.

"Hold on, can you sing that song again?" Astrid asked, grabbing a paper and pen.

Walter obligingly sang the melody again, while Astrid scribbled down the words.

"Look at this," she said, tilting the paper so Walter could see what she has written. "It's an acrostic. H-A-R-K-N-E-S-S. The words, they spell Harkness. Does that mean anything to you.?"

Walter froze.

He knew, suddenly, what the significance of the ditty was. He knew what he had to do.

"Will you excuse me for a minute, Astrix?" he said. "I need to make a call."

Without waiting for Astrid to reply, he walked across the lab and up the steps to his office. He closed the door, sliding the lock carefully into place. His hands shook as he picked up the phone and dialed.

"British Telephone Agency, how may I direct your call?" asked a calm, accented female voice.

"Yes, I'd like to talk to the - let me see - the, er, Mermaid Quay Travels Office in Cardiff, Wales, if you please." Walter hadn't forgotten the name, even after all these years.

"One moment please," said the opperator.

There was a long pause, then a dial tone. After several rings, a Welsh voice answered.

"Mermaid Quay Travels, Ianto speaking."

"Hello young man," said Walter. "I need to speak to Jack Harkness. It's a matter of some urgency."

"There's no one of that name here," said the man, Ianto. There was a slight tremor in his voice.

"What do you mean he's not there?" Walter asked impatiently. "Does he work somewhere else now, or is he simply out? I know at least he hasn't died since I knew him."

There was a long pause.

"How do you know Jack?" Ianto asked.

"We worked on some projects together in the 70s," answered Walter. His frayed nerves, already stretched tightly, were now at their breaking point. He had to try something, even if it didn't work. "Young man, does the word 'Torchwood' mean anything to you?"

There was another long pause.

"One moment please," said Ianto.

Jack picked up on the first ring.

"Harkness," he said.

"Harkness! It's me, Walter Bishop," said Walter.

"Bishop! I heard you got out of that institution, but I didn't believe it till now."

Walter smiled.

"Yes, well, I can't quite believe it myself."

"How are you?" Jack asked. "It's been a long time since the 70s when Torchwood collaborated with the American government."

"Even longer when you've spent 17 of those years in a mental institution," Walter said ruefully. "You sound the same, though. Like you haven't changed."

"I never do."

"Yes, a quality of yours I remember being particularly interested in."

"Listen, Bishop, if this is about you wanting to examine me again, there's not a chance," said Jack. "As fun as your poking and prodding was, you'll have to think of other ways of getting me naked than drugging me and shoving me in a sensory deprevation tank."

Walter couldn't help laughing at Jack's innuendo-laden tone.

"No, you haven't changed at all. But I didn't call to catch up. Do you remember I asked you to take care of some files for me, once a long time ago?"

"I remember," said Jack.

"Well, I need them."

"You told me to hide them for a reason, Bishop," Jack reminded him.

"Yes, but that was before I was missing parts of my brain," Walter explained. "I need them now. It's important - lives are at stake."

"Aren't they always?" Jack said, a note of humour in his tone. "When I heard you were working for Torchwood again, I wondered how long it would take you to contact me."

"We call it Fringe division now," Walter corrected him.

"You say tomato, I say secret government agency," replied Jack. "I hid the files. I'll email you their location, and you can pick them up yourself."

"I'd appreciate that," Walter said. Then, as Jack's words caught up with him, "You hid them here in America?"

Jack laughed.

"You'll see. Oh, are you still interested in research on other universes?"

Walter's thoughts flew to Peter, to the grave secret he was keeping from his son.

"Always," he said.

"And you're still looking for ways to cross over?"

"Yes," Walter affirmed.

"If you ever do get over there, do me a favour, will you? If you come across a girl, blond, east London accent, answers to the name of Rose, send her my way, will you? I have a friend who would very much appreciate her being returned to her own universe."

"I will," said Walter, thinking of Peter and the trouble he had had as a child in the wrong universe. "Thank you, Harkness."

"Till next time, Bishop," said Jack.

Walter nodded to himself, then placed the phone back in its cradle.

He hurred out into the lab, to the computers there. Astrid looked up from her books as he came in.

Walter ignored her curious look, and logged into his email. If he knew Jack, and thirty years ago, he had, then the email would already have been sent. Jack was nothing if not prompt. Sure enough, there it was in his inbox.

He scanned the email's contents, then gave a short laugh.

"Harkness Library," he muttered to himself. "How deliciously ironic."