Coronis has posted a summary.
Chapter begins with White trying to capture a wild Deerling but to no avail. Baker Chris accompanies her and cheers her up with bread. White receives a phone call, and Chris overhears her talking about returning an Agency Pokemon to its owner. The fact is, after White decided to take a ride on the Subway, she temporarily closes her Agency, and has thus returned all the bestowed Pokemon, except Gigi of course, since it ran away. She now needs Pokemon for her own use on the Subway, and is thus attempting a capture. (seems that the Subway ride is a long journey, not just a brief ride like in the games)
Black watches over White from afar with a sulk, and Marshal states that Black is upset that White gets to take the trial ride on the Subway instead of him. Black challenges why they can't take it together, and Marshal points out that White is just a beginner and it will be utterly unfair for them to battle together on the same platform. Marshal says as a man, he must show his support to his friends even if his own wish is compromised, and thus tosses Black towards where White is, and Black is obligated to teach White about battling.
The wild Deerling is already infuriated however, and starts chasing White around. She trips and it is about to stomp on her, but Servine suddenly saves her by whacking Deerling off with its vines. Black is shocked that the Servine is protecting White since they thought it was there to spy on them. He decides that White needs help to weaken the Deerling anyway and tells White to order a Leaf Tornado. To their surprise, Servine complies.
Black then decides to demo things first person to White, and spots a wild Tirtouga. He gets Tula out and attacks Tirtouga while White attacks Deerling similarly with Servine. At the end both successfully capture their Pokemon of choice.
Later, White is about to embark on the Subway. Tirtouga thrashes around in its Pokeball and causes it to fall out of Black's hands. Marshal recognizes it as the same Tirtouga he used to own but released back to the wild the day before because it was too stubborn to handle. He is amused that it ended up in Black's hands now.
Alder returns to join them, and wants to know if White wants to become stronger by taking the Subway. White explains that the sole reason she takes the train is for an important Pokemon who is now far away from her. She knows that there will come a day when this Pokemon will need to choose its path between battling and performing. She hopes that by that time, she will be there to support its choice, and since she knows nothing about battling, she must also explore the other path so that she may continue to accompany the Pokemon shall it choose battling. That is the reason she wants to take the trial ride.
White gets on board, and prepares to say her goodbyes to Black. Both are a bit emotional and thank each other for everything they're shared so far: 5 cities, 4 routes and 1 bridge. Black is at a loss of words, but then asks if he still owes White money for the broken cameras on their first encounter. White says there is indeed still some debt, and Black says he is still a staff of the BW Agency in that case. He promises to fulfill his own dream and advertise the logo of the Agency at the League when he wins. He wishes White good luck but the fast moving train is already drowning out Black's voice. Suddenly, White catches a Pokeball and sees that it is Brav. Turns out that it has volunteered to join White as she will need altogether 3 Pokemon to battle the Subway.
And so, Black and White go there separate ways. Black continues on his journey to counquer the League, while White explores her new journey with Brav, her newly captured Deerling, and a Servine whom she still has no idea whether it is a friend of foe.