Unfortunately I think you have confused a couple of terms that are quite specific within Moodle in your question.
However...
1. Any activity can be controlled using availability restrictions, so a specific activity cannot be attempted before a previous required activity. See: https://docs.moodle.org/32/en/Restrict_access
So you don't need a plugin to do this - its basic Moodle functionality - although your site does need to have restrictions enabled by the site Admin.
2. If you are talking about Lesson, e.g. the Moodle Lesson activity, then the same system of restrictions can be applied
3. "I don't want anyone moveing on until the time is right" - I don't think you are actually referring to "time" (which would require a different approach) - just the fact that there is an order of completion' - which the restrict access controls will give you.
Stu