Substituting the characters with their Half-Life counterparts, the story sees Freeman and the Lambda Resistance travel to the Arctic to board the Borealis, a ship with extradimensional technology that allows it to erratically travel through time and space, where they confront a myriad of alternative versions of themselves from different timelines.
sˈʌbstɪtˌuːɾɪŋ ðə kˈæɹɪktɚz wɪð ðɛɹ hˈæflˈaɪf kˈaʊntɚpˌɑːɹts, ðə stˈoːɹi sˈiːz fɹˈiːmən ænd ðə lˈæmdɚ ɹᵻsˈɪstəns tɹˈævəl tə ðɪ ˈɑːɹktɪk tə bˈoːɹd ðə bˌoːɹɪˈælɪs, ɐ ʃˈɪp wɪð ˈɛkstɹədᵻmˌɛnʃənəl tɛknˈɑːlədʒi ðæt ɐlˈaʊz ɪt tʊ ɛɹˈæɾɪkli tɹˈævəl θɹuː tˈaɪm ænd spˈeɪs, wˌɛɹ ðeɪ kənfɹˈʌnt ɐ mˈɪɹɪˌæd ʌv ɔːltˈɜːnətˌɪv vˈɜːʒənz ʌv ðɛmsˈɛlvz fɹʌm dˈɪfɹənt tˈaɪmlaɪnz.