A novel not for everyone but a spy novel like none other

Javier Marias's novel Your Face Tomorrow, vol 1: Fever and Spear is by no means a novel for all readers, but I find myself drawn to it and captivated, at least so far (100 pp., aboutt 25%). In essence, it appears to be a spy novel in which part of the mystery is whether it's a spu novel at all. The narrator, a Spaniard (Jaime Deza) from Madrid, living in England and purporting to be some sort of academic although it's totally unclear whether he really is or not, is at the outset in conversation with a much older (80-something) man who seems to be a mentor and perhaps erstwhile professor, Peter Wheeler, a Londoner. Wheeler asks Deza to attend a gathering at his house and keep an eye on one of the guests, Trupa, and report back on all of his observations. At the gathering, another Spaniard, de la Garza (?) attaches himself to the narrator, annoying him throughout the evening and making it nearly impossible for the narrator to carry out his "assignment." On the surface, thus far, it's a novel about a very uncomfortable social gathering with a lot of drinking and flirtation; but there's obviously more to this: Why is Wheeler so interested in Trupa? Who is Trupa? What's the narrator's connection to the two? Who send the other Spaniard to disrupt the narrator's efforts to gain information or insight? Wheeler himself? Some other agent? To this point, I'm interested and curious; the slow development and the many obscurities of these events may put some readers off, but I'm willing, at least to this point, to go along w/ Marias's pace and careful establishment of the premises of this complex, long novel. Like another Marias novel that I liked, The Infatuations, this is a novel that confounds us and draws us in, as it upends literary convention. Is this a spy novel at all?