While Touma and one of Misaka's many "sisters" ponder what to do about a stray cat, Mikoto herself has a rather more important fish to fry as she plans to take her attempts to stop the experiments going on using her likenesses by going to the very top of the tree, with every pun intended.
In short, with her attack on the facilities powering the experimentation surrounding Accelerator proving to have done little to dent their capabilities, Misaka instead decides to attack Tree Diagram, the sub-orbital supercomputer which calculates most of the research which goes on across Academy City. To brazenly infiltrate and hack into such a facility seems like a tall order even for a high-ranking Level 5, but the sole facility which communicates with Tree Diagram that serves as Misaka's target proves to be surprisingly quiet...
While all of this is going on, MISAKA has somehow managed to persuade Touma to take in the stray cat that she's been taking care of to the best of her abilities, but even as the two hang out and Touma heads into a store to look for some books on cat care, another experiment featuring the sisters is about to take place - the proximity of which to Touma's location could be about to make things decidedly more complicated.
For perhaps the first time in this series, this week's episode of A Certain Scientific Railgun S feels rather stretched out and slow-paced - you could probably even suggest that it's badly paced, with the big revelation about Tree Diagram being squeezed into the start of the closing credits while a lot of the episode was lost to Touma and MISAKA cooing over a cat. Now, I like cats as much as the next guy, but a lot of this dialogue and conversation didn't particularly feel like it added things to proceedings, which made things a little frustrating with so much more important material waiting in the weeks. Thankfully, it looks like we'll be well and truly back on track next week though.