Don't forget about faerie abilities, too. Burrow and sink will both block most of the damage heading your way, so you can hopefully use double attackers with them to take down as much HP as you can. Regeneration/restore/drain life/heal can be used with your remaining power (the best option depends on your and the furies' HP -- this is explained in the weapons recommendations thread, by Cranberry in the third post of the thread; she's also listed several inexpensive weapons by type there, too).
For defense, on the third turn, try using the Downsize! that was awarded in Tier 5. Earthen scorchstone and leaf shield might help if you need to go beyond 3 turns. Obviously, if you have a freezer or bomb, use that early.
I don't have the best weapons (I'm using double Ylana's blasters from TRoS, and the defensive weapons I listed above), but I have been training faithfully between plots, and it makes a world of difference (do try to train right now as much as you can; there's sure to be more battling to come, and you may be able to reach the next boost before the next opponents come). The strength and defense boosts come pretty close together at lower levels:
0 - 0.5
8 - 0.75
13 - 1.0
20 - 1.25
35 - 1.5
55 - 2.0
85 - 2.5
125 - 3.0
200 - 4.5
(These were copied from Cranberry's post; if you have a 6-icon weapon, at strength 0-7, it will only do 3 icons damage, but at strength 55-84, it will do 12 icons. If you have burrow and sink, I'd recommend cranking up your strength first. Because I'm at 200, my double Ylana's blasters mete out 108 icons of damage per turn, or over 150 when I could do a berserk attack and not worry about being killed.)
You may want to hold off buying weapons until after the plot is over (once prices fall back to normal levels), so you'll be ready for the next plot. The same is true for training: if you don't have codestones or dubloons stockpiled, and you won't make it to the next boost (keeping in mind that you can't train a stat beyond 2x level, except for HP) in the next couple of weeks, then wait until prices have fallen again to start training for the next plot.
I am glad to see that once you've exceeded the cap, TNT gives codestones and bottled faeries randomly ever few battles or so. This should help a little to combat typical plot inflation.
ETA: You can look up items on JellyNeo's item database, and then click on their price to see the price history.
Ylana's blasters are going for 1.2M; that's a 410,000 NP increase over August. In short, if you buy now, you'll be wasting nearly half a million NP. Other weapons may have inflated less; I'd recommend looking up ones on Cranberry's chart and comparing (and sharing what you learn with others here
). Of course, doing better in this plot will help you get better prizes (and possibly a new weapon), but I was still able to get 2 blasters from TRoS by doing little battling (though this plot may be more battle-intensive than TRoS was).
I've noticed that the new waves of opponents are coordinated, so we won't get more Furies until all the minions and brutes are gone. This helps with timing when to start refreshing to catch the Furies, so you don't waste quite so much time with the plot.