Its amusing. In this one, Flashman is in fine form, showing his competencies (fornication and horsemanship) and his true self (cowardly, lecherous and toadying). The basic of the story is that despite his best efforts for a soft billet, he winds up looking after a scion of royalty in Crimea. Along the way, he gets caught up in the charge of the Heavy Brigade, then the Charge of the Light Brigade, captured by the Russioans (and gives a interesting (horrifying) overview of Russian noble life), encounters Captain Count Ignatieff, survives a peasant uprising, escapes, is chased by Cossacks and wolves, recaptured, etc.
And that's not half of the book.
I'll admit its a pot boiler following the usual pattern of Flashman trying to avoid the sharp end, getting caught up in it anyway, meeting historical and interesting figures, and shagging any nice looking women along the way. Its not deep but its fun, giving the reader a nice overview of people, history and regions as it entertains.
I'll also suggest it for fans of SM Stirling's Peshawar Lancers which is a thinly disguised Flashman tribute.