The guys land in Baltimore on February 22, 1861, in a barn where a group of conspirators and followers of Abolitionist John Brown are meeting. They are mistaken for fellow collaborators, but the Pinkertons break up the meeting. Doug is captured while Tony escapes with brothers Jeremiah and Matthew. They still plan to blow up Lincoln, who is enroute to his inauguration. While Doug tries to convince Pinkerton he is innocent, Tony tries to persuade the brothers not to go through with there plan, but Jeremiah is determined. Tony manages to escape but Pinkerton doesn't believe him either. The two manage to convince Pinkerton there is a bomb and go to look for it. The Project staff have spotted the bomb and brought it to the future to disarm it, accidentally scooping up the conspirators' other, younger brother David. They convince David to delay the bomb before having to send him and the bomb back. As Lincoln departs, Tony, Doug, and brother Matthew manage to convince Jeremiah that his cause

Doug and Tony show up in June 1215 when the Earl of Huntington is trying to convince King John to sign the Magna Carta. Doug is captured along with Huntington when the King gets surly and orders their torture. Tony manages to rescue Doug and they flee where they meet up with Huntington's men: Little John, Friar Tuck, and the Merry Men. Using their knowledge of modern-day chemicals, Doug and Tony help the rebels while trying to get hold of a homing post that the Project staff has sent back to them to enact a rescue. With the time travellers help Huntington and his men capture King John and force him to sign the Magna Carta...at Runnymede! The homing post fails to work and the two are swept off.

Tony and Doug arrive near the Italian-Austrian Alps on October 23, 1915, as the Germans are preparing to bombard the area. An explosion knocks them out and uncovers the stone coffin of Emperor Nero. Nero's sword floats out of it, but kills a German soldier. They awaken and discover they are beneath the villa of Count Galba. He claims the two travelers are American friends, covering for them against the invading Germans. The ghost of Nero has other ideas, and wants to kill Galba, whose ancestor was responsible for Nero's death. First a German soldier then Tony are possessed by the ghost. The Time Tunnel project staff manage to free Tony with a high-powered electrical discharge on the recommendation of a Dr. Steinholtz, whom they call in. However, they then pull the ghost into the current day, but manage to send him back. Tony and Doug get Galba to safety and help lead the Italian resistance to the Germans. The German leader, Neistadt, flees but Nero's ghost delays him long enough for an