A Plymouth man pleaded not guilty to charges that he struck two pedestrians in Wareham with his vehicle and then fled the scene, said the Plymouth district attorney’s office. Kevin Spencer, 26, hit the pedestrians on Red Brook Road, said Bridget Norton Middleton, a spokeswoman for the district attorney. Spencer was later arrested at his home and arraigned Monday in Plymouth District Court. He pleaded not guilty to charges of drunk driving, second offense; leaving the scene of an accident causing personal injury; and other traffic offenses, Middleton said. One victim was listed in critical condition and the other in serious condition.