Second Foundation

Ahhhhh, it feels like it's been a year since I've read Foundation and Empire, and since the day I've finished the second volume of the Foundation saga, I've been wondering about the second Foundation and now, at least, I KNOW!!
I've found the first two volumes of the saga absolute "must-read"s and this third one is no exception!
This one comes in two parts, each part being neatly parted in chapters but, as usual, it all comes down to the last chapter. Let get into it thoroughly (so, as usual, ***SPOILER AHEAD***):

Part I: Search by the Mule
The Mule is now the emperor of the universe or rather, the "First Citizen of the Union" as he wants to be called. After having rapidly expanded, he has stopped for consolidation for 5 years, and his union is politically quiet and economically prosperous. But this apparent consolidation hides a ineffectual search for the second foundation: after his first failed effort by psycho-actively using Ebling Mis (see Foundation and Empire), he has been unsuccessfully raking the universe, looking for it: the first Foundation as been created in the broad daylight but the Second Foundation is an absolute mystery; the only information that is sure is that it is located "at the other end of the universe". As a new kind of effort, from his palace on the ex-pleasure world of Kalgan, he teams the former Foundation lieutenant -now Converted- Han Pritcher and the young, gifted, handsome -and Unconverted- Bail Channis together and asks Pritcher to let the other take the all initiative that his unconverted and therefore more creative mind offers.
All along the chapters, we are being offered, trough interludes, glimpses of the Second Foundation, through discussions between its highest members. They are all psychologists and are not hampered by physical speech anymore, so they do not strictly talk but rather understand each others. The Seldon plan is at a fracture point and to recover, they say that they need the Mule to find them...
Bail Channis quickly deduces that the Second Foundation could be on Tazenda, a quite forgotten world, and he and Pritcher embark for Rossem, one of its dominions, a chilly agricultural planet, in order to gather information on Tazenda. There they meet peasants, and the Elders of Rossem who make them wait... I won't delve into details, but the Mule has followed his lieutenants on Rossem: he confronts Bail Channis as a member of the Second Foundation while his fleet destroys Tazenda. Feeling that Channis is not desperate enough at the news of the possible destruction of the Second Foundation, the Mule mentally tortures him and learns his truth: Tazenda is not the second Foundation, Rossem is! The Mule orders his fleet to Rossem but there comes the First Speaker, leader of the Second Foundation. He explains the Mule that the plan created by Seldon is not a finished product, and that the second-foundationers are the guardian of this plan and finally, that Bail Channis' truth is not really the truth, but he was a volunteer for this mission and has been made to think that Rossem is the Second Foundation. While the Mule has a fraction of a second of inattention at this news, the First Speaker enters his mind and alters it. That is how the Second Foundation vanquishes the Mule.

Part II: Search by the Foundation
A quick history lesson informs us that after a change took place in the Mule's plan (which some says has been inspired by the Second Foundation), he has ruled as an enlightened despot for 5 year before dying. Then, his empire had slowly crumbled and the Foundation had risen again.
A generation has passed since the Mule died. Arcadia Darell, daughter of Dr Toran Darell, is the granddaughter of Bayta Darell, who defeated the Mule (see Foundation and Empire); she is a quick-witted teenager. About the Second Foundation, some believe it doesn't exist, some believe they guide the first Foundation, and among believers, most think that the Foundation need no blind guidance and want to control their own fates. Arcadia's father is specialized in encephalography and brain patterns and is leading a team of "secret conspirators" who are looking to find and defeat the Second Foundation; Arcadia likes to spy on them.
At an unknown place, the First Speaker introduces the Prime Radiant to a promising student. The Prime Radiant is a black cube containing the whole Seldon Plan; when he died, Seldon had 40% of the plan completed and since then, the plan has been completed, amended, corrected and reality-checked by second-foundationers. The whole plan could cover the wall of a large room with equations of a microscopic size. To enter Speakerhood, the student will have to make a contribution to the Plan. But right now, he learns that, after the Mule mess, the probability of success of the Plan is down to 20% or so and that the Second Foundation is currently working on a plan in the Plan -against the basic laws of psychohistory- with very low probabilities, involving the actions of individuals: another Seldon Crisis is looming.
The conspirators are a small group: Dr Darell, Homir Munn -a librarian who collects artifacts from the Mule- and some others, and Pelleas Anthor, a newcomer, student of an ex-colleague of Dr Darell. The science of encephalography is spurred by the interest in the Second Foundation, and the group has discovered the "Tamper Plateau", a plateau that shows on the graphs of persons who could have been tampered with, by the Mule or... the Second Foundation! Needing more information, they send Homir to Kalgan to investigate the inviolate Mule's palace, feeling that it could be under the influence of the Second Foundation. Homir goes, but Arcadia slips in his ship and goes with him.
Kalgan, after the death of the Mule, never reverted to a leisure world, and has stayed under the domination of self appointed "First Citizens". The current ruler of Kalgan, the killer of his predecessor, Lord Stettin hungers for the days where the Union was the ruler of the universe. Homir Munn asks lord Stettin to be granted access to the Mule palace but is rejected, that is until his favorite -more than friend but less than wife-, the Lady Callia makes him believe that Homir thinks that in the Seldon Plan, it is not said that the Second Empire must be that of the Foundation: it could be his.
Lord Stettin grants the access and after Homir's unsuccessful search, decides to start his conquest of the universe, and keeps him as a warranty that he is following the Seldon plan. Arcadia tries to flee from Kalgan, buys a ticket to Trantor and closely escapes a police search, helped by Preem Palver, a trading representative of a farm co-operative on Trantor, and his wife, two seemingly charming rednecks dubbed Pappa and Mamma. From Trantor where she is now stuck with Mamma and Pappa, Arcadia now knows -she doesn't know how, but she knows- where the second Foundation is and sends a 5 words message to his father.
Then, war is declared by Lord Stettin on the Foundation, and the First Citizen of the Union is rapidly expanding, with the strong fleet he has been massing for years. After several months of victories, he is trying for a big jab closer to the Foundation but they have prepared a bold trap and destroy his whole fleet: a Foundation victory it is! First witness of the kalganian defeat, Homir Munn thinks he knows the truth.

• Chapter 21: The answer that satisfied: The conspirators are reunited, and Homir Munn exposes his theory: there is no Second Foundation. Anthor confounds him and an encephalography reveals that Munn has been tampered with, certainly by the Second Foundation! Anthor then explain that he thinks the Second Foundation is on Kalgan, which has been the center of events recently. But Dr Darell thinks otherwise: the message he has received from his daughter is "a circle has no end" and indicates that the other end of the universe, to the Foundation, is... Terminus itself, and he believes that the Second Foundation is on Terminus. Then, he shows a little device he has been working on: a Mind Static, which creates randomly shifting wave patterns, to prevent a Second Foundation mind to read or control other minds. Pushed to the maximum, it acts to a powerful mind like a blinding light to an eye, it is a torture. And as it is turned on, Pelleas Anthor screams! He is a Second Foundationer, and confesses that the Second Foundation is on Terminus, that they are no more than 50 and that the Lady Callia is one of them. The last task is to make sure that Arcadia had not been manipulated: her encephalography shows no Tamper Plateau. Thus, it's over, Foundation is now free from the Second Foundation.
• Chapter 22: The answer that was true: Back to the First Speaker and his student for the real truth: to be able to get back on the track of the Plan, the first Foundation had to regain its confidence and forget about the Second Foundation so that they do not feel guided and act naturally according to the laws of the psychohistory. They (the Second Foundation) have arranged that the Foundation really beat a physical enemy in the ruler of Kalgan to regain its confidence; and they have seen to it that they believe that they've killed the Second Foundation. Thus, the Mind Static and science of encephalography, without any spurring, will decay. To attain this goal, they've been working for more than a decade, and they have manipulated Arcadia since she was a infant (and her mind a blank slate) so that the Tamper Plateau does not show! The First Speaker, Preem Palver (!) has brought the Seldon Plan back on track.

So great a story, I had to get into details and yet, I feel I did not do justice to the book: you just have to read it for yourself. To the next volumes now...