I usually treat chapter-by-chapter reading like detective work: my first move is hunting for the official home of 'Ransom'. Publishers, the author's own website, and official serialization platforms are where I start, because if chapters are being released legally online that's almost always the place they'll appear. Many authors serialize on their own sites, or use services like
wattpad,
Royal Road,
webnovel, or even Patreon — and those will explicitly state whether the chapters are free, paywalled, or for supporters only.
If you don't see anything on the author's page, check major retailers and library apps. Kindle, Kobo,
google play books, Apple Books, and physical/eBook sellers will list ISBNs and publication details; sometimes novels are sold chapter-by-chapter or have sample chapters available. Public library services like Libby/OverDrive and Hoopla are great legal alternatives too — you can often borrow the eBook or audiobook legally without paying per chapter. Also look for official apps or publisher portals — they sometimes release serialized content chapterwise.
Stay away from sites that aggregate content without clear publisher or author permission. Those are often infringing copies and can carry malware. If a chapter appears on a forum or an upload site with no attribution, it's risky. In short: if it's on the author's or publisher's platform, or a reputable retailer/library, it's legal; if it's popped up on sketchy aggregate sites, it's not. Personally I feel better supporting creators directly whenever possible — it keeps the series coming and avoids the guilt of pirated reads.