Official availability for PT-BR subtitles can be limited on some international platforms.

If you tell me what specific part of the film or the "Rubikon" project you're interested in, I can look for more or expert reviews in Portuguese. Rubikon - Prime Video

After a global catastrophe covers Earth in a mysterious toxic fog, the crew of the sophisticated space station Rubikon must choose between staying safe in their self-sufficient habitat or risking their lives to search for survivors on the planet. Cast: Julia Franz Richter, George Blagden, and Mark Ivanir. Where to Find Legendas (Subtitles) in PT-BR

If official platforms lack PT-BR support, users often look for community-created subtitles on sites like Legendas.tv or OpenSubtitles , though these require careful file-matching with your video source.

For a full Portuguese synopsis and details, you can visit the IMDb Ponto Sem Retorno page.

These platforms often host the film, but availability varies by region. Check your local Google Play Movies or Amazon Prime Video page to see if "Português" is listed under the "Legendas" or "Idiomas" section.