Let me start right of by saying that this, the fourth novel in Trollope's Palliser-series, is to my mind the best in the series so far (I still have the last 2 to read of course). It is on the one hand everything one comes to expect from a good Trollope-novel, and on the other hand is clearly different.
At the start of the story Phineas is living a respectable but uneventful life in Dublin, working as a lawyer. His wife Mary has died giving birth to their still-born child, and Phineas must acknowledge to himself that he misses the thrill of his earlier career as an MP in London. So when he is asked if he will stand again in the elections he jumps to the opportunity, although fully aware that his money will soon run out unless he can obtain a job in some or other government office.
Phineas is elected and finds himself back in Parliament, full of high hopes and grand ideas (misguided, as he will duly learn) to participate in the democratic government of the country. But before long, things start to fall apart: in his election campaign Phineas pleaded for church disestablishment, only to find that his party opposes the very same measure, which leaves but two alternatives for Phineas,neither of them very attractive: either to vote with his party (in other words go back on the promises he made in his election campaign), or to vote against his party (which would probably keep his conscience clear but ruin his chances of obtaining a government post).
In his private life too, not all is as it should be. Whereas his easy charm used to make him the favorite of all the noble ladies in London society, his relations with them now seem to have become difficult and awkward. Lady Laura Kennedy (whom he once proposed to) is living separated from her husband and Phineas, though he is aware that she loves him passionately, also feels he cannot answer her love. Simultaneously, Phineas himself comes to realize that he loves Madame Max Goesler but is afraid to speak out because a few years earlier he rejected her offer of marriage.
And then, to top things of, Phineas' political rival Mr. Bonteen is murdered and the (circumstancial) evidence all points to Phineas who finds himself on trial for his life...
As I said in the beginning, 'Phineas Redux' has all the characteristics of a typical Trollope-novel: the easy, colloquial style, the amazing 'credibility' of the characters' emotions, feelings and actions, the immaculate way in which the plot is constructed, always wanting you to learn what 'happened next'. However, it is also very different in tone from earlier novels (most of all 'Phineas Finn', the second novel in the series). Whereas in 'Phineas Finn' our hero is overjoyed when he fulfills his dream of becoming an MP and basks in the political life, he now very soon becomes disillusioned with it all when he comes to realize that politics (also) equals petty scheming, power play and a rat race for well-paid jobs.
The ultimate blow to Phineas' belief in the entire political and judicial system comes when, innocent as he knows himself to be, he must face a murder-charge and feels that people he once considered friends now all of a sudden regard him with suspicion. As Phineas' outlook on the world becomes much gloomier, so does the novel's tone. In a way, this is the reverse situation of Josiah Crawley in 'The Last Chronicle of Barset': he doubts his own innocence (and, at times, even sanity) while his friends never do, whereas Phineas knows himself to be innocent but sees the suspicion building all around him.
In short, this is a tremendously good book with plenty of food for thought about honesty, truth, frustrated love, thwarted ambitions... It's the sort of book I would (and will) recommend ad nauseam to friends and acquaintances, and will definitely read again myself in the future. But first it's on to part five in the Palliser-novels, 'The Prime Minister'!