Trees came a year later, in 1972. During the subsequent tours to promote the latter, Fleetwood once more adopted the role of mediator. Kirwan's self-destructive personality and problems with alcohol culminated in a refusal to go on stage before one concert; Fleetwood himself made the decision to fire the band member. Furthermore, there were early signs of strife in the marriage of John and Christine McVie. Fleetwood again stepped in to mediate between the two members, talking Christine out of a decision to leave the group. The band added guitarist Bob Weston and vocalist Dave Walker, formerly of Savoy Brown and the Idle Race. The resulting turmoil, however, negatively affected their next album, Penguin, released in 1973 to poor reviews. Walker was subsequently asked to leave the group, and the next album Mystery to Me was received more warmly. In October 1973, Fleetwood instructed Weston—who had engaged in an affair with Fleetwood's wife—to leave Fleetwood Mac. Meanwhile, manager Clifford Davis began to lead a separate group of musicians under the name 'Fleetwood Mac', and his increasing legal assault on the original group pushed Fleetwood and his fellow band members to consider managing themselves. Fleetwood took on more managerial responsibility and leadership over the group. Heroes Are Hard to Find, Fleetwood Mac, Rumours In 1974, the band moved to Los Angeles, where they recorded the album Heroes Are Hard to Find. By November 1974, Bob Welch had left the band. Meanwhile, Fleetwood was planning a follow-up album to Heroes Are Hard to Find – Welch's last with the group – which had charted at #34 in the US. Fleetwood was shopping with his children when a chance encounter with an old friend led him to visit Sound City and producer Keith Olsen. While at the studio, Olsen played samples from an album entitled Buckingham Nicks. Fleetwood immediately "was in awe". On New Year's Eve, 1974, Fleetwood contacted Olsen to advise him that their planned project was on hiatus after Welch's departure, however, he then suggested that Nicks and Buckingham join Fleetwood Mac. The group ate together with Nicks and Fleetwood at a local restaurant before practising together for the first time in the new studio. The next year, the new line-up released Fleetwood Mac. The album proved to be a breakthrough for the band and became a huge hit, reaching No.1 in the US and selling over five million copies. Fleetwood