Gladiator in arena consilium capit.
The Gladiator makes (his) plan in the Arena.
(Seneca, Epistolae 22.1)
The point being, making a plan in the arena is too late! One needs to plan ahead in order to succeed.
Nota Bene, the Latin idiom to "take" (capere) a plan (consilium) rather than the English idiom "to make a plan."
It's a bargain at 0.99 cents on Kindle (or affordably priced at $11.90 on paperback).
You'll travel back to ancient Rome on a harrowing mission to save the modern world. It's the adventure of four lifetimes.