Tab does not manage it that year.

Or the next, or the next few.

But she doggedly tries every visit, because there are no better ideas going, everything has some dreadful flaw, everything makes her map fall to bits or Aelise thinks it's untenable per risk aversion. Aelise may not like using Chelsa - or says so, anyway - but she doesn't consider her quite as much of a disaster as Tab does, so she passes up a couple possibilities Tab would have jumped on.

And one day, a few weeks after she turns twelve -

"It - I think it - did it work?"