Cold War, hot tempers and feverish dreams of betrayal, oh, my.

They all slither about in "The Company," an aspiring miniseries epic about the CIA that is sometimes extremely gripping and sometimes not so much.

But thanks to sleek production values, a generally top-notch cast and an absorbing overall story that smartly mixes explosive action with quieter moments of sinister intrigue, "The Company" delivers a refreshingly solid jolt of summertime Big Event drama.

Unfolding for six hours over the next three Sunday nights, the ambitious miniseries, which stars Chris O'Donnell, Alfred Molina and Michael Keaton, opens for spy versus spy business at 8 p.m. EDT Sunday on TNT.

"The Company," based on a best-selling historical novel by Robert Littell that mingles fictional and real characters, serves up free-floating espionage heebie-jeebies right from the start. It episodically weaves the story of the CIA's early years in the 1950s. It then sweeps forward through America's bungled involvement in the Hungarian Revolution of 1956, the harrowing Bay of Pigs fiasco in the early 1960s and finally to the collapse of the Soviet Union in 1991.

Happy endings? You won't find them in the story of idealistic young Yale graduate Jack McAuliffe (O'Donnell). He's has just been recruited into the fledgling Central Intelligence Agency along with classmate Leo Kritzky (Alessandro Nivola, "Junebug"). Jack's ultimate destiny _ big surprise - is bitter disillusionment.

Meanwhile, long before the youthful idealism curdles, the third member of the close-knit trio of Yale friends, Yevgeny Tsipin (Rory Cochrane, "CSI: Miami"), returns to his Russian homeland, where he's enticed into his own shadowy spy life of deception as a KGB operative.

Quickly, O'Donnell's do-right Jack comes under the charismatic influence of rumpled, hard-drinking CIA mentor Harvey Torriti (Molina), who is known as the Sorcerer. They first tangle with their Soviet rivals in the KGB while on deep, deadly undercover assignment in the dangerous backstreets of Berlin during the 1950s.

It is in Germany that Jack and the Sorcerer first become scarily convinced that a mole has been sabotaging their missions.

And they're not the only ones suspicious about a traitor in their CIA midst.

Say a creepy hello to James Angleton (Keaton), a famously eccentric, chain-smoking CIA counterintelligence expert who becomes obsessed with the belief that a mole has indeed breached the agency's top-secret inner workings. The manipulative Angleton's a brilliant, paranoia-stoked pip. He jabbers on about his convoluted theories and a Cold War spying life wandering in "the wilderness of mirrors."

Unfortunately, gravitas-free Chris O'Donnell, though a chummy enough presence in lightweight entertainments, is the one notable weak link.

Luckily, Molina, Nivola and Cochrane are superb throughout. Director Mikael Salomon ("Band of Brothers") also has a firm grip on the sprawling global odyssey.

And Michael Keaton is just sensational. Whenever he's onscreen, "The Company" roars to spooky, enthralling life It's his best performance in years.

Cynical, bleak and emotionally dark, "The Company" explores the Cold War and the CIA's history of missteps through a decidedly pessimistic prism. But thanks to Michael Keaton & Co., this often tautly wound miniseries also delivers the undeniable pleasures of a ripping good espionage yarn