When you awaken, you feel no pain, but you also find that you can't move. You can't quite tell whether you've been expertly strapped down or you've been paralyzed by the mad doctor's drugs. You hear an old-fashioned printer screeching and see the doctor examining a large readout scrolling out of it on green-and-white paper; there is a monolith of tape wheels and blinking lights in front of her, comprising the entire wall to your right. There also seems to be a little silver-gray robot standing behind her.
"Ah, I'm glad to see you're awake," she comments, smiling and turning to face you. "Look who's happy to see you!" The robot barks and make a panting noise through a little loudspeaker on the front of its muzzle. A metal rod at the back of the bot is waving back and forth. You don't understand why she's showing you an artificial dog, as adorable as it may be. You wanted her to give you back your real dog, not just build you a mechanical pet.
"Where is Lucy? Did it work? Is she okay?" you ask, your voice sounding oddly tinny somehow.
"Obviously, I couldn't bring her back biologically. There would be ways of doing so, but most of them only work within minutes of death. Fortunately, I'm well-known (infamous, some would say) for my work on technological immortality."
You think you understand what she's talking about (especially since you've started adjusting to her accent and happen to be a scifi nerd yourself). "So, you uploaded Lucy's brain into a machine and downloaded her into this robot?"
"Oh, heavens no," she responds dismissively. "For one thing, even my highly experimental laboratory isn't advanced enough to simulate the canine brain with a computer that small. The robot dog itself only contains motors, sensory inputs, wifi adapters, and enough processing capability to maintain a two-way link with this giant mainframe right here. All of her thinking and feeling goes on within the massive processing unit beside you. If she were to leave this building and the wireless network it contains, she would simply black out, and her robot body would go limp until someone carries her back within range."
You kind of feel bad for Lucy knowing that she's stuck here living out such a meager remnant of her existence stuck within a cold metal shell. But at least the doctor kept her promise in what sounds like the only way possible. You couldn't bear to go on unless your beloved companion could also survive in some fashion. You couldn't understand why the doctor would have needed to incapacitate you, though. Your question was about to be answered.
"Second," she continued, "Lucy's brain had already been dead too long. The only person I knew to have sufficient information about her for my software to assemble a behavioral reconstruction was you. The Lucy you see before you is YOUR Lucy: an amalgam of your conscious and subconscious memories of her. To achieve this, I had to make sure the computer knew everything you knew, all the way down long-forgot details from years ago. I had to give it full control over and unrestricted access to the deepest and most intimate sections of your mind."
"Wait, are you saying that ... ?"
"Yes, I uploaded YOUR brain. You can't leave the facility any more than she can, because you're really there inside the mainframe, too. You'll get to live here with me, sharing your immortality with your beloved pet, for as long as we retain the ability to simulate your neural connections." She glanced at the computer readouts again. "Ah, I see your avatar's motor control tranceivers are finally coming online. You should be able to look down and see your robot body any second now."
You wondered if maybe it would turn out to be just a sick practical joke. And then you finally looked down and saw your barrel-like metal torso and your hydraulic legs and arms. Lucy seems aware of your distress and clangs over on her metal paws to nuzzle you. The doctor wasn't kidding when she said saving Lucy would be expensive! It seems to have cost you your whole body. You raise your metal arm and twiddle your geared fingers, marveling that it's all from just a wifi connection to the mainframe. You aren't even really in the androids head, much less your own! You look down again at your robot pet and lower your mechanical arm to pat her head.