The Fifth Doctor receives a summons, and he and Peri land in a castle in medieval England. He steps out to explore, telling Peri to wait in the TARDIS. Going through a door, he meets his first three incarnations. Not long after that, a future incarnation arrives, having also been summoned. The five Doctors talk, deciding to play something to pass the time, as they don't know who summoned them all here. The First Doctor pulls out a deck and states that they will play poker to pass the time. Since he has an injured arm, he deals. He tells the other Doctors that they will play for a golden bow. As they play, the First Doctor explains what happened to him.
He had gotten the bow as a reward from the emperor of Gallutia, for convincing his enemies to surrender, an event that none of the other Doctors remember, with the exception of the Second Doctor, who only vaguely remembers it. After winning the bow, the First Doctor landed here alone to do some archery practise. On the scanner he saw a girl being held by bandits. He rescued her and brought her into the TARDIS. When the bandits ran away, he tried to let the girl out, but was surrounded by men in armour. He closed the door on them. The knights were angry with him for interfering with their bandit pursuit. When he attempted to let the girl, Lady Mary, out of the TARDIS, one of the men claimed he had seen the TARDIS materialise out of thin air. The others were afraid of the Doctor's magical powers. They grabbed him, and were about to kill him, but he was able to escape. He found this castle and closed the drawbridge. The knights followed, then got extra men and surrounded the castle. The Doctor was trapped here, away from his TARDIS.
The Fifth Doctor realises that the First Doctor summoned his later incarnations here to help him. The bow was given to him by an emperor, but it wasn't supposed to be used as a weapon. The First Doctor needs one of the others to help him, as his arm was injured by the knights. The loser of the poker hand will have to face the knights and explain what happened.
The Fifth Doctor loses the hand, and the First Doctor gives the bow to him. He uses his TARDIS to travel to a spot near the First Doctor's TARDIS, then sends his TARDIS, with Peri in it, back to the castle. The knights appear, greeting him with swords drawn. One of the knights, Henry, threatens to kill him, but he petitions to talk to their leader, Sir Edward.
Edward arrives, interrupted in his plans to rescue his sister Mary. The Doctor suggests they send one knight with him to the TARDIS so he can retrieve Mary. Edward decides to kill him, but the Doctor then offers him the golden bow. Edward allows Henry to accompany the Doctor to the TARDIS.
In the TARDIS, Henry sees that Mary is safe. He brings Mary outside and lets the Doctor go. The Doctor quickly gets into the First Doctor's TARDIS and heads back to the castle, while the knights are distracted by Mary's safe return.
The other Doctors congratulate him on his success, but soon realise that they can no longer remember what it was the Fifth Doctor gave to Edward. Suddenly, Peri enters the room, but she's looking for the Sixth Doctor, instead of the Fifth. The Sixth Doctor tells her to get back into the TARDIS, but it's too late as this future version of Peri catches sight of the Fifth Doctor, who she is shocked to see, considering that she witnessed the Fifth Doctor's regeneration. The Sixth Doctor leaves with her before she can say anything else on the matter, leaving the Fifth Doctor with the knowledge that his next regeneration will occur sooner than he expected.
- Of the incarnations not present, the "taller chap with the teeth and the scarf" refused the summons and the "younger, handsome one, with hair dangling to his shoulders" didn't respond. The First Doctor didn't bother to summon the "short Scottish fellow" because he would "turn things to his own ends".
- The First Doctor decides to get in some archery practise while Ben and Polly are visiting an old friend.
- The stories in Short Trips: Zodiac are inspired by the signs of the zodiac. This story's theme is Sagittarius.
- The First Doctor feels that he will regenerate soon. (TV: The Tenth Planet)
- The Third Doctor mentions that he and Sarah Jane Smith once encountered medieval humans. (TV: The Time Warrior)