After Hashem gives Moshe instructions about going to Par'oh, he goes back to Egypt and is greeted by Aharon. They speak together and then convene the Council of Elders of Zion (!) (the zekainim) and Moshe and Aharon tell them what they are going to do and show them the signs from Hashem. They believe and respond positively. The Torah then says that Moshe and Aharon then went to Par'oh.
Rashi tells us that the Zekainim all disappeared on the way to Par'oh and that is why they are not mentioned here where they should also have been. They were so afraid of Par'oh's reaction that they slipped away (thinking they were not going to be missed) and by the time Moshe and Aharon got to the palace, none of the zekainim were left. They were paid back for this later when the Torah was given at Sinai, the zekainim were not allowed to approach the mountain with Moshe.
There are times when a person, and especially leaders, have to step up to the plate. There was a great need for leadership and they could not perform, preferring instead to slip away. If one shows that he is unworthy of stepping up to the plate and being the leader people can rely on, you will get what you deserve. When you want the glory, you won't be part of it then either.