On a roof top overlooking a canal a figure dressed in black waited patiently for a cloud to cover the moon and provide a shield of darkness. An observer below would not have seen the crossbow bolt that crossed the gap between the buildings trailing a silken cord behind it. The cord had been carefully died with black squid ink so that it was effectively invisible against the sky above. The figure carefully pulled on the cord and was relieved to feel the grapnel at the far end lodge against a balustrade on the other roof top, and then tied the cord around a chimney, making it secure. The two buildings were now connected, albeit tenously.
The figure pulled back their hood to reveal an elfin face, surround by a shock of red curls. Donnatella realised that she had been holding her breath ever since she had fired the crossbow bolt and grapnel, and slowly exhaled. This part had been easy. She dismantled the cross piece of the bow and stashed it in the back pack at her feet, along with the handle. She wouldn't need it again, but she couldn't leave it behind. The next task was to remove five short sections of dark wood from her back pack, each about a foot in length, but with a screw thread and connector at either end that allowed her to assemble them into a single five foot staff. She balanced the staff experimentally in her hands, letting it slide between her fingers as she found its centre of gravity.
Now would come the most dangerous part of the night's activities.
She raised herself on to the rope and checked that the grapnel still held her weight. It did. She dismounted again and took a tinder box and a small phial from the pocket of her jet black cloak. The phial held an acrid substance with the consistency of thick honey and she proceeded to coat a section of the cord at the point at which it was tied to the chimney breast. The final act was to strike the tinder - it took three attempts before the flint produced a satisfactory spark and ignited the section of cord. It burned with an odd, purplish flame and she knew that there was now no way of smothering it or extinguishing. The Greek fire that she had purchased from the alchemist hadn't been cheap, but it was worth its weight in gold. She now had less than three minutes before the cord would burn through to the point of snapping, so there was no time to waste.
She mounted the rope again and started to cross the gap between the buildings, using the staff to aid her balance. A noise from below distracted her. A small scull was being propelled up the canal by a pair of rowers - evidently somewhat the worse for drink judging by the bawdy song that one of them was crooning and the clink of a bottle or jug of some sort. She had planned to cross unnoticed but now she would have to hope that neither of the pair in the boat would choose this moment to look up.
She made a concious effort to steady herself and not to rush, risking falling to her certain death below. A breeze started to pick up, blowing from the east and carrying the salt tang of the marshes beyond the lagoon. Half way across now, steady does it, she thought. The breeze had an unforseen consequence - when she had tested the time it would take for a section of cord to burn through she had been indoors where the air was still. Now the flames were being strengthened and made hotter and more vigourous by the air, and the rope gave an alarming lurch as it started to fray and give way.
"Bones of the Saint preserve me now" she whispered and launched herself forward, taking two steps and then reaching for the parapet in front of her. She gripped hard with one hand, holding her staff with the other, as the rope snapped and she thumped hard into the side of the building. She bit back a cry of pain and pulled herself up on to the roof, coiling the rope behind her. The rowers were now well past her position, and the sound of their carrousing would have covered the sound of her body hitting the brick work.
She paused to catch her breath and rub her bruised ribs before stashing the rope. She knew that she must leave no evidence of her presence at all. Time to move on. She had studied the architects plans carefully and knew that there should be a trap door in the roof leading down into an upper room, and indeed, the entrance was exactly where she expected.
She started to lift the heavy oak door and then caught herself as the rusted hinges started to squeak and groan in protest. This was not the time to allow the possibility of drawing any sort of attention to herself, so she removed a second phial from her cloak, this one containing a light oil, almond in colour. She carefully allowed a small amount to fall on each hinge and waited for it to penetrate the rusted metal. Now when she lifted the door, the sound was almost inaudible and she looked down into the empty space below.
A ladder led down from the opening into what appeared to be a store room of sorts. Crates of various sizes were piled in haphazard fashion, and dust sheets covered a large painting propped against the longest wall. She memorized the layout and the began to climb down the ladder, carefully closing the trap door behind herself.
She was inside.