Dear Friends

Dear Friends follows a high-school student named Rina (played by Keiko Kitagawa)
who believes that friends are not necessary and that they can only be
used in times of need. Thus, she is unable to maintain a decent
relationship with her friends and classmates. Her family's relationship
is also lacking; her father does not care much about his family and her
mother is over-protective.
Rina spends a lot of her time going to a club where Yousuke (played by Masaya Kikawada) is the disc jockey with her friends Hiroko (played by Airi Toriyama) and Emi (played by Hatsune Matsushima).
(In the opening scene, Rina has "borrowed" Hiroko's boyfriend for sex,
infuriating Hiroko.) Yousuke falls for Rina, but her attitude has a
feral edge, and they neck but stop short of having sex.
After obtaining a large amount of money under false pretenses (i.e.
claiming she is pregnant when she is not and forcing the guy [not
Hiroko's boyfriend or Yousuke] to pay for the abortion) and spending it
on a bottle of Dom Pérignon (which she sprays over everyone at the club), Rina collapses on the dance floor. She eventually discovers that she has cancer (non-Hodgkin lymphoma)
and becomes hospitalized for an indefinite amount of time. In the
hospital, she is not visited by her family, but by one of her
classmates named Maki (played by Yuika Motokariya).
Although Maki tells Rina that they were friends in primary school, Rina
does not remember her, so Maki takes the opportunity to re-connect with
her. A young girl, Kanae, (played by Mao Sasaki) who is also hospitalized tries to become friends with Rina, but she holds fast onto her mantra of friends being unnecessary.
Throughout her hospitalization, Rina begins to lose hope as her
well-being falls apart, and she decides to jump off the hospital
rooftop as she feels that no one no longer cares about her. Her hair
falls out from the chemotherapy and she looks pale and thin. Rina
learns that Kanae also had cancer, and has died after a bone marrow
transplant failed. Rina must undergo a mastectomy
as the cancer has spread to her left breast, and feels that suicide is
the best way out of her predicament. However, she is confronted by
Maki, who stabs herself in the chest with a knife and declares that she
will share the same pain as Rina and that she does not want to lose her
friend. Maki has suicidal tendencies (as evidenced by scars on her
wrist), but sees in her relationship with Rina a reason to keep living.
Rina shows some hope again when she realizes that she can find
friendship in Maki, but she does not see Maki while Maki recovers from
the stab wound.
Hiroko and Emi then visit Rina in the hospital ward. Hiroko throws
away a love letter from Yousuke to Rina that she was supposed to
deliver, then claims that she and Emi had three-way sex with him. Emi
acknowledges this (even though it is news to her). Rina tosses both of
them out.
After treatment, Rina is discharged. She tries to go back to her
party lifestyle, but cannot force herself to behave as she once did.
She goes back to the club, where Emi apologizes for the hospital visit
(claiming that Hiroko put her up to it) and states that Hiroko
overdosed on drugs. Rina decides she is ready to have sex with Yousuke,
but he has second thoughts after seeing Rina's mastectomy scar.
Rina goes back to the hospital rooftop to jump, but is stopped by
the head nurse. The nurse says that Maki wanted her to live, but Rina
claims that Maki has not seen her recently. Then, a nurse pushes a
wheelchair-bound zombie-like Maki onto the rooftop, who says that the
only reason she is still living is so that she could meet friends like
Rina. Maki has a terminal illness: an unspecified neurodegenerative disease. Rina finds her purpose in life, transforms into an angel of mercy, applies to nursing school, and cares for Maki during her final days.