The Zeo to Turbo Transistion Gap is an infamous and consistently disputed sequence of untelevisied events that took place in between the season finale of Power Rangers Zeo, and the premiere of Turbo: A Power Rangers Movie, which were never properly ellaborated on. Attempts by fans to satisfy thier own curiousity over the events that occured in this gap period led to the notorious Scorpion Rain hoax, which in turn inspired Forever Red.
During the events of this gap, many characters vanished, or resumed previous roles they had in the series, or in some cases dissapered entirely, or mainly in the interm before returning
According to multiple early script drafts for the second PR movie, a more concrete explanation for the Zeo Powers being destroyed was intended for the theatres, but the decision to make the film less dependent on continuity and draw in audiences that had drifted away from the series over the years may have been a factor in trying to increase the series declining ratings.
Lord Zedd and Rita Repulsa
At the conclusion of Good as Gold, Lord Zedd and Rita Repulsa succeeded in crippling The Machine Empire by mortally wounding their leaders, essentially regaining their power base on the moon. By the time we see them in Turbo: A Power Rangers Movie however, the two have apparently given up on their efforts to seize the Earth and strike back at the Rangers. Rita simply advises Divatox by phone to "run" when the galactic pirate asks her for advise on dealing with The Rangers. The precise location of Rita and Zedd in this movie is unknown
If the events of Scorpion Rain are to be considered canocial, Zedd attempted to destroy Earth with a fully operational Serpenterra, managing to succesfully cripple the Zeo Zords and destroy the Super Zeo Zords before being forced to crash-land on the moon and be driven from our section of the galaxy entirely. They eventually resurfaced and were instructed by Dark Spectre to attack the Vica Galaxy, where Zordon's wave purified their souls and turned them to the side of good.
The Machine Empire
Despite having their bodies destroyed by Rita and Zedd, King Mondo, Queen Machina, Prince Sprockett, Klank, and Orbus are seen to have been fully rebuilt by the time we see them again in Power Rangers In Space. It can be assumed that, having failed to establish themselves as an independent entity, as well as being put in their place by UAE loyalists, the Empire's leaders elected to return to the alliance and help support Dark Spectre's carefully coordinated campaign of terror on the galaxy. It is Spectre's campaign which also eventually forces Divatox to abandon her own agendas on Earth in Chase Into Space.
In Forever Red, Tommy points out that he and the remaining Zeo Rangers eventually crippled The Machine Empire by defeating their leaders, this is contradicted by the events of Countdown to Destruction, where it is made clear that the Zordon Wave, which was triggered by Andros shattering Zordon's energy tube, was responsible for reducing King Mondo, Machina, Sprockett, and much of the Machine Empire legions to dust. In this instance, it is entirely possible that the Zeo Rangers were active during this storyline and were waging a war in space against the Machine Empire, managing to eliminate Prince Gasket and Archerina, with the Machine Generals managing to escape.
Bulk and Skull
Perhaps one of the more glaring plot omissions is the lack of resolution to Bulk and Skull's undercover assignment to Paris, for which they abandoned Detective Stone and left his Detective Agency to collapse without any support. Nevertheless, by the time we see them again in the second movie, both they and Stone have reconciled and been rehired by the Angel Grove Police Department.
Jason Lee, the former Red Ranger and later Gold Ranger, had only recently lost the Golden Powers, and had elected to spend time with his Aunts and a girl he had met at Ernie's Beach House. Jason is later revealed in Turbo: A Power Rangers Movie as having only recently returned to Angel Grove along with Kimberly, indicating that this decision to stay didnt last long.