Remember: you can always correct me in terms of grammar since I don’t claim that mine is perfect. Just do it nicely. While I suggest not to tell me anything about the story... only because it’s not finished yet! XD
Thirteen knows that interfering with the laws of time is something that must be done with care and not for selfish reasons. And yet, once again, the Timelady is ready to bend those laws in order to save Lara, especially because she wishes that her adoptive daughter dies of old age, surrounded by her loved ones. Which is something that the Doctor could never do even if she lived long enough to die of old age: her loved ones died on Gallifrey (chibeco.altervista.org/Scrittu…). However, this time Thirteen, remembering that the TARDIS prevented her from saving Gallifrey by its destruction (while the time machine allowed her to save Lara from The Great Intelligence because it was an alternate timeline created by the latter, chibeco.altervista.org/Scrittu…), wants to find another way, so she does some research and learns about “The Triangle of Light”, an item that would grant its wielder control over time and space. The item is scattered in pieces throughout the Earth and, in order to work properly, these pieces must be found and joined by the final phase of a planetary alignment that culminates in a solar eclipse and which occurs every 5.000 years. What a coincidence, now it's almost time to join these pieces!
The Timelady would like to consult Madame Carvier, knowing that she always liked Lara and that she would help the Doctor in her quest. However, the Doctor can’t do it, because that would mean involving both the Cybermen and the U.N.I.T. that keep her as a prisoner (chibeco.altervista.org/Scrittu…). And while Thirteen can count on the CyberKing (he once told her that he had thought about asking Verdilet to make him come back human, when he and Missy were still in Ireland, chibeco.altervista.org/Scrittu…. However, he stayed silent and let Missy express her wish to get a humanoid female body because he owed and still owes his second life to her), she’s not sure that she can rely on the U.N.I.T. as well.
Sofia could say nothing about reviving Lara and not her late father Jacob, but the Doctor chooses to not tell her anything because Sofia still misses him so much that she’d probably do anything to get him back (chibeco.altervista.org/Scrittu…).
Now it’s time to take in consideration Jessica, Kevin, Carter and Zip.
Carter is a human/Osirian hybrid (chibeco.altervista.org/Scrittu…), so he’s like a Timelord, while Zip is human. Thirteen likes the idea of this duo so similar to the one made by herself and Lara. Thus Carter and Zip could understand her need to keep Lara by her side as much as possible (but to be fair, the Timelady always gave Lara a chance to live a life of her own, like when the archaeologist was engaged to the Earl of Farringdon, chibeco.altervista.org/Scrittu…).
Kevin is her son and Jessica is Lara's daughter (chibeco.altervista.org/Scrittu…): they could understand her mother/aunt’s wish that Lara lives as much naturally as possible, particularly Jessica, who is as old as her own mother.
After a brief consultation, all four agree to help the Doctor and swear not to say a word about this mission to anyone else.
Now... what about Lara? The Doctor “suggests” to her to go on a mission on her own, that is finding and destroying the Pandora’s box, an artefact that contains a deadly plague, at least according to some ancient legends. Thirteen doesn’t say that this way she wants to restore her adoptive daughter’s confidence that she’s still more than capable of saving the world, despite her being human and not so young anymore. The Timelady is, in fact, concerned that Lara somehow feels inferior to what is essentially an (alien) younger version of herself that also possesses considerable powers. The Doctor also tells Lara about her longing to have an adventure with Carter, Jessica and Kevin, as she never spent any quality time with them so far. Lara voices her perplexity because she remembers the last time that she and the Doctor went on separate ways. But Thirteen promises to Lara that what happened in Egypt won’t happen again (chibeco.altervista.org/Scrittu…), thanks to the fact that she won't go completely solo. What she doesn’t tell her adoptive daughter is that Carter already promised that he would kill the Timelady if she became the Valeyard at some point (the same promise that the CyberKing, who at the time was still CyberLarson, made to both the Doctor and Missy, when they both faced Seth/Sutekh for the second time).
Finally, the Doctor recommends Lara not to tell Madame Carvier about the Pandora’s Box, for fear of making her want to get it for herself, despite the fact that the Cybermen and the U.N.I.T. have her under their surveillance. Plus, Thirteen tells the archeologist that Zip confessed to her that he misses the old days with Lara and that he would like to help his former employer at least once again (actually the Timelady, thinking that it would be too suspicious leaving Lara without any allies, asked Zip to offer his services to Lara and stay silent about the other mission, not speaking a word even with Jonah, in case he gets an invitation from Lara and decides to join the party).
Lara accepts the “suggestions” and so both the adventures begin.
Carter asks and obtains a meeting with Manfred Powell, a lawyer who seems to know one thing or two about a clock that is the key to join the halves of the Triangle. The archaeologist shows up with the Doctor (that assumed the human alias of Danielle West, an aspiring archaeologist mentored by Carter, thanks once again to the "Earthly" Slitheens, chibeco.altervista.org/Scrittu…), Jessica and Kevin. During the conversation, Manfred senses that Danielle is much more experienced than Carter, but doesn't say a word about it. In the end, the quartet leaves without acquiring any new information, but Kevin reveals that he left a micro spy camera back at Manfred’s house because he suspected that the man knew so much more than what he claimed to know. This way the quartet learns that Manfred owns the clock, but that he doesn’t know the locations of the two halves of the Triangle, despite having assured the Illuminati, the secret society he belongs to, of the contrary. In addition, the lawyer seems to be a rebel member of the Illuminati, because he wants to use the Triangle for himself.