Two men were seriously injured early Saturday morning in a hit-and-run accident in Plymouth, according to Plymouth police. Captain John Rogers said Kevin Spencer, 26, of Plymouth, was arrested and charged with fleeing the scene of an accident after the two men were struck around 2 a.m. Rogers said that a 27-year-old man was taken to Boston Medical Center with critical injuries. A 30-year-old man was taken to Tobey Hospital in Wareham with serious injuries. Spencer was being held on $10,000 bail, Rogers said. He is scheduled to be arraigned in Plymouth District Court on Monday morning.