Among the deadliest fighters in Nazi-occupied Holland were a trio of schoolgirls barely out of pigtails.

Sisters Freddie and Truus Oversteegen, along with their friend Hannie Schaft, started small: stealing documents, circulating banned publications and passing along messages to underground resistance fighters.

But before long, these sweet young things — ages 14, 16 and 19 when the Nazis invaded in 1940 — had formed a lethal gang that planted bombs and gunned down German soldiers as well as Dutch collaborators.

As fresh-faced teenagers, they were unlikely to be suspected of anti-fascist activities, allowing them to operate under the noses of the Nazis and, if need be, flirt their way out of trouble.

The amazing true story is told by St. Paul author Tim Brady in "Three Ordinary Girls," an account of the trio forced by war into roles as spies, saboteurs and assassins — heroes who traded their schoolbooks for guns.

The Nazi occupation of countries throughout Europe revealed fault lines in those societies. Who would resist the brutal invaders? Who would collaborate with them? And who would assist the Jews, their fellow citizens marked for ruthless extermination?

Brady's subjects chose to fight. The Oversteegen sisters were raised by a single mother with fervent socialist and Communist sympathies. Schaft was a law student whose highly protective parents tried to shield their only child from the world's encroaching evil.

Joining the resistance in their hometown of Haarlem, a city on the fringe of metropolitan Amsterdam, the young women soon distinguished themselves by the bold courage with which they carried out their assignments. In time, they became prolific "liquidators" of Nazi oppressors and the Dutch citizens who assisted the jackbooted thugs.

The girls' signature tactic in bicycle-dependent Holland was the drive-by shooting on a bike, coolly pedaling away after gunning down their target.

Having seen the atrocities visited on their friends and fellow countrymen by the Nazis, the girls didn't have any moral qualms about fighting back.

"It was a necessary evil," Freddie Oversteegen recalled years later. "I felt no pity." Her sister agreed.

"There was really only one solution," Truus Oversteegen said. "Shooting."

Brady paints a compelling picture of the fear, tragedy and paranoia of living in an enemy-occupied land. Heroism and betrayal exist side by side; mistakes are made in the fog of war.

The author builds drama slowly — perhaps too slowly. A prologue might have been a good idea, giving the reader an early taste of the excitement to come.

But ultimately, his book succeeds as a tale of how extraordinary circumstances call forth the unexpected strength of ordinary people.

John Reinan is a Star Tribune reporter. • 612-673-7402

Three Ordinary Girls

By: Tim Brady.
Publisher: Citadel, 304 pages, $26.