Synopsis: Finding the border between performance art and animal cruelty is the theme of this unusual one-off Seventh Doctor adventure.
The Doctor's off for a bit of museum spotting, when he opens the TARDIS doors to find himself in a jungle. In one corner of the jungle is a massive staircase. At the foot of the stairs is an egg, which suddenly hatches. The resulting creature matures extremely rapidly, gaining the ability to breathe fire within seconds. Using his new-found ability, the creature bakes a brick from the dirt at the jungle and begins to ascend the staircase with it. The creature takes the brick to the top of the stairs and adds it to the rest, bringing the construction project one step closer to completion. He is just preparing to hurl himself over the edge of the staircase to his death, when the Doctor attempts to stop him.
Just then, the genetic sculptor Garg Ardonquist appears. He chastises the Doctor for interfering with an art form he cannot understand. The cycle of birth, advancement of the staircase and death is meant, he says, to represent an artist's struggle to create.
As he's explaining this to the Doctor, though, the creature leaps at Ardonquist, forcing both of them off the staircase, and to their deaths. The "genetic sculpture" is thus terminated, itself unfinished. The Doctor escapes in the TARDIS as bemused security guards enter the sculpture and begin dismantling the staircase, brick by brick, for resale as "collector's items".