原告也去 The Accuser Goes Too
玉帝又吩咐：「原告也去。」行者道：「老孫也去？」四天師道：「萬歲已出了旨意，你可同金星去來。」行者真個隨著金星，縱雲頭，早至雲樓宮。玉帝又吩咐：「原告也去。」行者道：「老孙也去？」四天师道：「万岁已出了旨意，你可同金星去来。」行者真个随着金星，纵云头，早至云楼宫。
逐句解 Line by line
The Jade Emperor gave a further instruction: "The accuser goes too."
原告 is the plaintiff, the party who brought the case, and it is still the legal term. Four characters of imperial speech, and they are the ones that put Pilgrim in a room with the man he is accusing.
Pilgrim said, "Old Monkey goes as well?"
The nerve deserts him for exactly one line. He wanted a summons issued; he did not expect to have to be there when it was served.
The four Celestial Masters said, "His Majesty has issued the edict. You may go along with the Gold Star."
萬歲 is ten thousand years, the standing form of address for an emperor and, by extension, a way of referring to him. The Celestial Masters answer him the way a clerk answers anybody: the order has been made, so there is nothing to discuss.
Pilgrim did indeed follow the Gold Star. They rode the cloud head and were soon at the Cloud Tower Palace.
著 is zhe, following and going on following — Pilgrim trailing along behind a senior official, which is not a formation this novel puts him in very often.
One four-character order changes the whole shape of the chapter. Pilgrim had planned to start a process and watch it work; instead he has to walk into the accused man's house beside the officer serving the summons.
His one moment of hesitation is worth more than a paragraph of characterisation. He will face anything with a weapon in it, and he balks at an awkward conversation.