The idea that there is “ascension” in the degrees is a common misperception. The main branch of Freemasonry, usually referred to as the “Blue Lodge” (first three degrees) teaches you everything, philosophically, that Freemasonry purports to teach.
The other bodies, degrees, etc., are more or less variations on the same themes. The York Rite leans towards more of a Christian perspective, the Scottish Rite is more of a philosophical examination of the principals. Since the scottish rite has many more degrees, they look at several other virtues closely related to the character traits lauded in the first three degrees. Joining an appendant body ENHANCES your knowledge, moreso than revealing something new. A sort of equivalent would be, if you were learning about the American civil war, and read only one general overview book on the war, vs. learning about the civil war by reading many books from many authors.
It bears repeating here that the Shrine is an organization FOR Masons and run by Masons, but is not Governed by a Masonic Grand Lodge—for all legal intents and purposes Shrines are independent organizations that just happen to require that members be Masons. Same goes for the Grotto and Tall Cedars and any of the other corrollary bodies I’m forgetting.
The “secrets” the other degrees keep are the passwords, modes of recognition, and the exact nature of how they present their lessons. Although, from the Masons I’ve met, they are a lot more loose lipped about these with other Masons than we Masons generally are with non-members.
-P.S. “The Order”...none of us use that jargon!