Phase I of Zenith ran from Prog 535 (15 Aug 1987) to Prog 550 (28 Nov 1987) of 2000 AD. It was first collected by Titan as Zenith Book One: Tygers. It was later reprinted in The Best of 2000AD Monthly issues 99 (December 1993) and 100 (January 1994) as Zenith: Year One.

Phase I is set in 1987, and deals with the return of Masterman, the Nazi superhuman last seen in the Second World War. Ruby Fox, one of the surviving members of the 1960s superhuman group Cloud 9, attempts to rally all the remaining superhumans to fight him. Zenith, the youngest superhuman, is more concerned with his career as a pop star. He is the offspring of two members of this group who disappeared nineteen years ago, presumed dead; and it is the chance to learn what happened to them that persuades him to take part.

• Prologue: Ground Zero
• 1: Dropping In
• 2: Blow Up
• 3: Shock Treatment
• 4: History Lessons
• 5: Corridors of Power
• 6: Patterns
• 7: Fear of Flying
• 8: Enter the Dragon!
• 9: Storm Warnings
• 10: Burn, Baby, Burn!
• 11: London's Burning
• 12: Mind Games
• 13: Into the Absolute Elsewhere
• 14: Famous Last Words
• Epilogue