He relaxes his wings and tail, draws the chains around his neck and wrists again, draws another chain around Tialle's neck (with an apologetic kiss to the statue's muzzle that is probably not part of the story), and bundles the both of them into the same remote underground cell. Then, seemingly as an afterthought, he closes his hand around the air beyond Tialle's broken horn and makes a snapping-off motion.

So: himself and Tialle, imprisoned together, her horn being broken either before she got there or just as she arrived. At first he cowers away from her, and (he indicates with more mime around the statue) she from him. Then they come closer together. Closer.

He lays his hand slowly, deliberately, against her horn. A hiss and an artful shudder remind Isibel that this would have hurt quite a lot.

Moving quickly, he breaks the imaginary chains around each of their necks, then the ones around his wrists. Creative mime, with some limping and fluttering, indicates that he was too weak or injured to stand; he crawled to the door of their prison and broke it open with only a little more difficulty than he had with the chains.

And then, apparently, Tialle stood still with some reluctance while he hauled himself onto her back, and he guided the pair of them all the way through the tunnels and up to the surface, and they proceeded in this way across a considerable distance before they finally parted ways. (A hand clawing illustratively down the scarred membrane of his wing indicates why he did not just fly away at that point.)