so taakaki actually already found out that hina and hinako is two different persons. Taketora had got hina's school bag,found her phone and used some sort of tools to recharge and switch on her smartphone only to find out hina's frm the future but at that time he doesn't know that hina and hinako is a two different person and thought that hinako is frm the future and she was lying to all the ppl around her until he confronts her with hina's smartphone and a gun is pulled against hinako(he thinks hinako is some sort of spy or smtg and she can be a dangerous person,bt he doesn't have the mean to kill her tho) one time hinako purposely ask takaaki to hold a gathering in his courtyard in order to meet with taketora, shocking,confusing and saddened by the confrontation and the fact he hold a gun against her,hinako bursts into tears and telling him the truth about her and hina. She also promised to bring him to hina once she finds out whr is hina's whereabouts.
And lastest chapter 39, hina,hinako and taketoru have meet with each other. Taketoru has returned the necklace to hina and tell her that the necklace is actually an important device in the deformation of connected space-time structure (google translate here coz nt knw how to accurately translate this sentence/term) and he wonders why the necklace would end up being her great grandma's possessions. Anyway, there's a way to return to the future and if hina has made her decisions she can go to taketoru and he will help her to. Another thing is taketoru is also from the future,but it is way faraway future than hina's (there is a scene with taketoru wearing a weird tight-fitting jumpsuit and short bob hair lol).
Actually there's more bt too lazy to go through the other details
and if you guys are interested can go and read the chinese translation. Just copy and search for ---- 泪雨和小夜曲